Cellectis (CLLS) 6-K/A 31 Aug 21 2021 Q2 Current report (foreign) (amended) Financial data

Cover Page

Cover Page	6 Months Ended
	Jun. 30, 2021
Document Information [Line Items]
Document Type	6-K/A
Amendment Flag	false
Document Period End Date	Jun. 30, 2021
Document Fiscal Year Focus	2021
Document Fiscal Period Focus	Q2
Entity Registrant Name	Cellectis S.A.
Entity Central Index Key	0001627281
Current Fiscal Year End Date	--12-31

Statements of Consolidated Fina

Statements of Consolidated Financial Position - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Non-current assets
Intangible assets	$ 1,584	$ 1,584
Property, plant, and equipment	79,478	71,673
Right-of-use assets	74,050	73,845
Other non-current financial assets	22,101	7,007
Total non-current assets	177,214	154,109
Current assets
Inventories	2,468	1,606
Trade receivables	3,878	5,171
Subsidies receivables	5,654	10,703
Other current assets	16,733	29,643
Current financial assets	3,393	27,091
Cash and cash equivalents	248,226	241,148
Total current assets	280,352	315,362
TOTAL ASSETS	457,565	469,471
Shareholders' equity
Share capital	2,947	2,785
Premiums related to the share capital	920,591	863,912
Currency translation adjustment	(9,602)	(4,089)
Retained earnings	(586,284)	(505,961)
Net income (loss)	(51,787)	(81,074)
Total shareholders' equity - Group Share	275,865	275,573
Non-controlling interests	26,458	33,273
Total shareholders' equity	302,323	308,846
Non-current liabilities
Non-current financial liabilities	23,475	28,836
Non-current lease debts	75,763	75,764
Non-current provisions	3,610	4,010
Other non-current liabilities	948
Total non-current liabilities	103,797	108,610
Current liabilities
Current lease debts	7,691	6,696
Trade payables	28,254	24,609
Deferred revenues and contract liabilities	423	452
Current provisions	1,397	1,131
Other current liabilities	13,681	19,127
Total current liabilities	51,446	52,015
TOTAL LIABILITIES AND SHAREHOLDERS' EQUITY	$ 457,565	$ 469,471

Statements of Consolidated Oper

Statements of Consolidated Operations - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Profit or loss [abstract]
Revenues	$ 11,176	$ 2,900	$ 36,777	$ 52,993
Other income	3,439	1,716	5,804	3,494
Total revenues and other income	14,615	4,616	42,581	56,487
Operating expenses
Cost of revenue	(11,754)	(5,827)	(19,899)	(10,428)
Research and development expenses	(31,147)	(22,862)	(62,338)	(43,587)
Selling, general and administrative expenses	(9,343)	(9,070)	(18,219)	(21,213)
Other operating income (expenses)	150	111	488	86
Total operating expenses	(52,096)	(37,647)	(99,968)	(75,142)
Operating income (loss)	(37,481)	(33,031)	(57,387)	(18,655)
Net Financial gain (loss)	(4,129)	(2,821)	431	(635)
Income tax	0	0	0	0
Net income (loss)	(41,610)	(35,852)	(56,956)	(19,290)
Attributable to shareholders of Cellectis	(39,919)	(32,263)	(51,787)	(12,221)
Attributable to non-controlling interests	$ (1,691)	$ (3,589)	$ (5,169)	$ (7,069)
Basic / Diluted net income (loss) per share attributable to shareholders of Cellectis
Basic net income (loss) attributable to shareholders of Cellectis per share ($ /share)	$ (0.88)	$ (0.76)	$ (1.17)	$ (0.29)
Diluted net income (loss) attributable to shareholders of Cellectis per share ($ /share)	$ (0.88)	$ (0.76)	$ (1.17)	$ (0.29)

Interim Statements of Consolida

Interim Statements of Consolidated Comprehensive Income (Loss) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Statement of comprehensive income [abstract]
Net income (loss)	$ (41,610)	$ (35,852)	$ (56,956)	$ (19,290)
Actuarial gains and losses	137	189	577	143
Other comprehensive income (loss) that will not be reclassified subsequently to income or loss	137	189	577	143
Currency translation adjustment	2,714	5,534	(6,969)	(634)
Commodity derivative contracts		(3)		(58)
Other comprehensive income (loss) that will be reclassified subsequently to income or loss	2,714	5,531	(6,969)	(691)
Total Comprehensive income (loss)	(38,759)	(30,132)	(63,348)	(19,838)
Attributable to shareholders of Cellectis	(37,034)	(26,611)	(56,661)	(13,206)
Attributable to non-controlling interests	$ (1,725)	$ (3,521)	$ (6,688)	$ (6,632)

Statements of Consolidated Cash

Statements of Consolidated Cash Flows - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020
Cash flows from operating activities
Net income (loss) for the period	$ (56,956)	$ (19,290)
Reconciliation of net income (loss) and of the cash provided by (used in) operating activities
Amortization and depreciation	7,173	4,199
Net loss (income) on disposals	4	9
Net financial loss (gain)	(431)	645
Expenses related to share-based payments	4,020	9,427
Provisions	433	(1,897)
Other non cash items	2	0
Gain upon the forgiveness of the Payroll Protection Program loan	(1,528)
Convertible note received for up-front license fee classified in non-current assets	(14,904)
Interest (paid) / received	(1,422)	2,809
Operating cash flows before change in working capital	(63,610)	(4,099)
Decrease (increase) in inventories	(866)	(2,813)
Decrease (increase) in trade receivables and other current assets	4,325	(2,159)
Decrease (increase) in subsidies receivables	4,787	3,690
(Decrease) increase in trade payables and other current liabilities	2,330	3,782
(Decrease) increase in deferred income	(19)	(19,167)
Change in working capital	10,556	(16,667)
Net cash flows provided by (used in) operating activities	(53,054)	(20,766)
Cash flows from investment activities
Acquisition of intangible assets	(23)	(41)
Acquisition of property, plant and equipment	(13,641)	(21,891)
Net change in non-current financial assets	(93)	(1,958)
Sale (Acquisition) of current financial assets	23,698	(29,993)
Net cash flows provided by (used in) investing activities	9,941	(53,882)
Cash flows from financing activities
Proceeds from the exercise of stock options Cellectis	11,818
Proceeds from the exercise of stock options Calyxt	227	179
Increase in share capital Cellectis	46,924	1,518
Payments on lease debts	(6,339)	(3,594)
Net cash flows provided by (used in) financing activities	52,630	(1,898)
(Decrease) increase in cash and cash equivalents	9,518	(76,546)
Cash and cash equivalents at the beginning of the year	241,148	340,522
Effect of exchange rate changes on cash	(2,439)	(3,266)
Cash and cash equivalents at the end of the period	$ 248,226	$ 260,711

Statements of Changes in Consol

Statements of Changes in Consolidated Shareholders' Equity - USD ($) $ in Thousands		Total	Share Capital Ordinary Shares [member]	Premiums Related to Share Capital [member]	Currency Translation Adjustment [member]	Retained Earnings (Deficit) [member]	Income (Loss) [member]	Attributable to Shareholders of Cellectis [member]	Non controlling Interests [member]
Beginning balance at Dec. 31, 2019		$ 355,470	$ 2,767	$ 843,478	$ (22,641)	$ (406,390)	$ (102,091)	$ 315,123	$ 40,347
Beginning balance, shares at Dec. 31, 2019			42,465,669
Statement [Line Items]
Net Loss		(19,290)					(12,221)	(12,221)	(7,069)
Other comprehensive income (loss)		(548)			(1,089)	104		(985)	437
Total Comprehensive income (loss)		(19,838)			(1,089)	104	(12,221)	(13,206)	(6,632)
Allocation of prior period loss						(102,091)	102,091
Exercise of share warrants, employee warrants, stock options and free shares vesting			$ 1			(1)
Exercise of share warrants, employee warrants, stock options and free shares vesting, Shares			20,464
Transaction with subsidiaries						(155)		(155)	155
Non-cash stock-based compensation expense		9,427		5,844				5,844	3,583
Balance at end of year at Jun. 30, 2020		345,059	$ 2,768	849,322	(23,730)	(508,533)	(12,221)	307,606	37,453
Ending balance, shares at Jun. 30, 2020			42,486,133
Beginning balance at Dec. 31, 2020		308,846	$ 2,785	863,911	(4,089)	(505,961)	(81,074)	275,572	33,273
Beginning balance, shares at Dec. 31, 2020			42,780,186
Statement [Line Items]
Net Loss		(56,956)					(51,787)	(51,787)	(5,169)
Other comprehensive income (loss)		(6,393)			(5,451)	577		(4,874)	(1,519)
Total Comprehensive income (loss)		(63,348)			(5,451)	577	(51,787)	(56,661)	(6,688)
Allocation of prior period loss						(81,074)	81,074
Exercise of stock options Calyxt ,Values		227				146		146	81
Capital Increase Cellectis (ATM)		47,834	$ 146	47,688				47,834
Capital Increase Cellectis (ATM), Shares			2,415,630
Transaction costs	[1]	(910)		(910)				(910)
Exercise of share warrants, employee warrants, stock options and free shares vesting		5,718	$ 16	5,702				5,718
Exercise of share warrants, employee warrants, stock options and free shares vesting, Shares			265,494
Transaction with subsidiaries		(1)				(6)		(6)	5
Non-cash stock-based compensation expense		4,020		4,233				4,233	(213)
Other movements		(62)		(34)	(62)	34		(62)
Balance at end of year at Jun. 30, 2021		$ 302,323	$ 2,947	$ 920,591	$ (9,602)	$ (586,284)	$ (51,787)	$ 275,864	$ 26,458
Ending balance, shares at Jun. 30, 2021			45,461,310
[1]	These costs correspond to the issuance costs related to the At-The-Market (“ATM”) financing program were recorded as a reduction of share premium, in anticipation of share issuances that occurred in April 2021

The Company

The Company	6 Months Ended
	Jun. 30, 2021
Text block1 [abstract]
The Company	Note 1. The Company Cellectis S.A. (hereinafter “Cellectis” or “we”) is a limited liability company (“société anonyme”) registered and domiciled in Paris, France. We are a clinical stage biotechnological company, employing our core proprietary technologies to develop products based on gene-editing with a portfolio of allogeneic Chimeric Antigen Receptor T-cells Our UCART product candidates, based on gene-edited T-cells CAR-based T-cells. T-cells, T-cells “off-the-shelf” Together with our focus on immuno-oncology, we are using, through our platform, HEAL, our gene-editing technologies to develop HSC product candidates in genetic diseases. As of June 30, 2021, Cellectis S.A. also owns 64.4% of the outstanding shares of common stock of Calyxt, Inc., our plant-based biotechnology platform subsidiary that is focused on deploying its core strengths in research and development, including gene editing, plant breeding, and trait development, toward developing high value, sustainable and plant-based innovations with substantial disruption potential. Cellectis S.A., Cellectis, Inc., Cellectis Biologics Inc. and Calyxt, Inc. are sometimes referred to as a consolidated group of companies as the “Group.” COVID-19 While implementing health and safety measures in response to the COVID-19 T-cell Although the COVID-19 AMELI-01, BALLI-01 MELANI-01 Despite the increasing availability of COVID-19 COVID-19 T-cell patient follow-up COVID-19 COVID-19 At Calyxt, during the first half of 2021, the COVID-19 COVID-19 The overall impact to Cellectis’ and Calyxt’s businesses will be dependent on future developments, which are highly uncertain and difficult to predict.

Accounting principles

Accounting principles	6 Months Ended
	Jun. 30, 2021
Text block1 [abstract]
Accounting principles	Note 2. Accounting principles 2.1 Basis for preparation The Interim Consolidated Financial Statements of Cellectis as of, and for the three- and six-month The Interim Consolidated Financial Statements are presented in U.S. dollars. See Note 2.2. The Interim Consolidated Financial Statements as of, and for the three- and six-month The Interim Consolidated Financial Statements as of and for the three- and six-month IFRS include International Financial Reporting Standards (“IFRS”), International Accounting Standards (“the IAS”), as well as the interpretations issued by the Standards Interpretation Committee (“the SIC”), and the International Financial Reporting Interpretations Committee (“IFRIC”). Application of new or amended accounting standards or new amendments The following pronouncements and related amendments have been adopted by us from January 1, 2021 but had no significant impact on the Interim Consolidated Financial Statements: • Interest Rate Benchmark Reform – Phase 2: Amendments to IFRS 9, IAS 39, IFRS 7, IFRS 4 and IFRS 16. The amendments provide temporary reliefs which address the financial reporting effects when an interbank offered rate (IBOR) is replaced with an alternative nearly risk-free interest rate (RFR). • Amendments to IFRS 16 Leases: Covid-19-Related Accounting standards, interpretations and amendments issued but not yet effective The following pronouncements and related amendments are applicable for accounting periods beginning after January 1, 2022. We do not anticipate that the adoption of these pronouncements and amendments will have a material impact on our results of operations, financial position or cash flows: • Amendments to IAS 37 – Onerous Contracts: Cost of Fulfilling a Contract (Effective for the accounting periods as of January 1, 2022) • Amendments to IAS 16 – Property, Plant and Equipment: Proceeds before Intended Use (Effective for the accounting periods as of January 1, 2022) • Amendments to IFRS 3 – Reference to the Conceptual Framework (Effective for the accounting periods as of January 1, 2022) • Amendments to IAS 8 – Definition of Accounting Estimates (issued on 12 February 2021 and Effective for the accounting periods as of January 1, 2023) • Amendments to IAS 12 – Income Taxes: Deferred Tax related to Assets and Liabilities arising from a Single Transaction (issued on 8 May 2021 and Effective for the accounting periods as of January 1, 2023) 2.2 Currency of the financial statements The Interim Consolidated Financial Statements are presented in U.S. dollars, which differs from the functional currency of Cellectis, which is the euro. We believe that this presentation enhances the comparability with peers, which primarily present their financial statements in U.S. dollars. All financial information (unless indicated otherwise) is presented in thousands of U.S. dollars. The statements of financial position of consolidated entities having a functional currency different from the U.S. dollar are translated into U.S. dollars at the closing exchange rate (spot exchange rate at the statement of financial position date) and the statements of operations, statements of comprehensive income (loss) and statements of cash flows of such consolidated entities are translated at the average period to date exchange rate. The resulting translation adjustments are included in equity under the caption “Accumulated other comprehensive income (loss)” in the Statements of Changes in Shareholders’ Equity. 2.3 Consolidated entities and non-controlling Accounting policy We control all the legal entities included in the consolidation. An investor controls an investee when the investor is exposed to variable returns from its involvement with the investee and has the ability to affect those returns through its power over the investee. Control requires power, exposure to variability of returns and a linkage between the two. To have power, the investor needs to have existing rights that give it the current ability to direct the relevant activities that significantly affect the investee’s returns. In order to ascertain control, potential voting rights which are substantial are taken into consideration. Consolidation of a subsidiary begins when the Group obtains control over the subsidiary and ceases when the Group loses control of the subsidiary. All intra-Group assets and liabilities, equity, income, expenses and cash flows relating to transactions between members of the Group are eliminated in full in the consolidation. Consolidated entities For the six-month As of June 30, 2021, Cellectis S.A. owns 100% of Cellectis, Inc., which owns 100% of Cellectis Biologics, Inc., and approximately 64.4% of Calyxt’s outstanding shares of common stock. Non-controlling Non-controlling non-controlling follow-on

Information concerning the Grou

Information concerning the Group's Consolidated Operations	6 Months Ended
	Jun. 30, 2021
Text block1 [abstract]
Information concerning the Group's Consolidated Operations	Note 3. Information concerning the Group’s Consolidated Operations 3.1 Revenues and other income 3.1.1 For the six-month Revenues by country of origin and other income For the six-month period ended June 30, 2020 2021 $ in thousands From France 48,323 20,061 From USA (1) 4,670 16,716 Revenues 52,993 36,777 Research tax credit 3,573 4,272 Subsidies and other (2) (79 ) 1,532 Other income 3,494 5,804 Total revenues and other income 56,487 42,581 (1) Revenues from USA concern Calyxt only. (2) As of June 30, 2021, this only includes Calyxt’s PPP loan, which is now forgiven and recognized as other income such as disclosed in note 10.1. Revenues by nature For the six-month period ended June 30, 2020 2021 $ in thousands Recognition of previously deferred upfront payments 19,535 — Other revenues 27,536 20,014 Collaboration agreements 47,071 20,014 Licenses 1,233 — Products & services 4,689 16,763 Total revenues 52,993 36,777 Recognition of other revenues for the six-month right-of-use Revenues related to licenses include royalties received under our various license agreements. Products and services revenues mainly include the revenues of plants activities which are primarily attributable to Calyxt’s seed and grain crop sales for $16.7 million during the first half of 2021. 3.1.2 For the three-month period ended June 30 Revenues by country of origin and other income For the three-month period ended June 30, 2020 2021 $ in thousands From France (3) 607 (552 ) From USA (1) 2,293 11,728 Revenues 2,900 11,176 Research tax credit 1,725 1,909 Subsidies and other (2) (10 ) 1,530 Other income 1,716 3,439 Total revenues and other income 4,616 14,615 (1) Revenues from USA concern Calyxt only. (2) As of June 30, 2021, this only includes Calyxt’s PPP loan, which is now forgiven and recognized as other income such as disclosed in note 10.1. (3) As of June 30, 2021, the negative impact corresponds to Cytovia’s convertible note revaluation for the three months ended March 31, 2021 which has been reclassified to financial result in the three months ended June 30, 2021. Revenues by nature For the three-month period ended June 30, 2020 2021 $ in thousands Recognition of previously deferred upfront payments — — Other revenues (1) 110 (551 ) Collaboration agreements 110 (551 ) Licenses (1) 466 (48 ) Products & services 2,324 11,775 Total revenues 2,900 11,176 (1) As of June 30, 2021, the negative impact corresponds to Cytovia’s convertible note revaluation for the three months ended March 31, 2021 which has been reclassified to financial result in the three months ended June 30, 2021. 3.2 Operating expenses 3.2.1 For the six-month For the six-month period ended June 30, 2020 2021 Cost of goods sold (9,204 ) (18,706 ) Royalty expenses (1,223 ) (1,194 ) Cost of revenue (10,428 ) (19,899 ) For the six-month Research and development expenses 2020 2021 Wages and salaries (13,276 ) (20,863 ) Social charges on stock option grants — (845 ) Non-cash (5,014 ) (4,530 ) Personnel expenses (18,290 ) (26,237 ) Purchases and external expenses (21,743 ) (30,897 ) Other (3,555 ) (5,204 ) Total research and development expenses (43,587 ) (62,338 ) For the six-month Selling, general and administrative expenses 2020 2021 Wages and salaries (7,890 ) (9,183 ) Social charges on stock option grants — (350 ) Non-cash (4,413 ) 509 Personnel expenses (12,302 ) (9,024 ) Purchases and external expenses (6,980 ) (6,419 ) Other (1,931 ) (2,776 ) Total selling, general and administrative expenses (21,213 ) (18,219 ) For the six-month period ended June 30, Personnel expenses 2020 2021 Wages and salaries (21,165 ) (30,046 ) Social charges on stock option grants — (1,195 ) Non-cash (9,427 ) (4,020 ) Total personnel expenses (30,592 ) (35,261 ) 3.2.2 For the three-month period ended June 30 For the three-month period ended June 30, 2020 2021 Cost of goods sold (5,320 ) (11,375 ) Royalty expenses (507 ) (380 ) Cost of revenue (5,827 ) (11,754 ) For the three-month period ended June 30, Research and development expenses 2020 2021 Wages and salaries (6,790 ) (9,986 ) Social charges on free shares and stock option grants — (84 ) Non-cash (2,410 ) (2,819 ) Personnel expenses (9,200 ) (12,888 ) Purchases and external expenses (11,775 ) (15,845 ) Other (1,887 ) (2,413 ) Total research and development expenses (22,862 ) (31,147 ) For the three-month period ended June 30, Selling, general and administrative expenses 2020 2021 Wages and salaries (3,105 ) (3,206 ) Social charges on free shares and stock option grants — (17 ) Non-cash (2,240 ) (1,172 ) Personnel expenses (5,345 ) (4,395 ) Purchases and external expenses (2,653 ) (3,600 ) Other (1,072 ) (1,348 ) Total selling, general and administrative expenses (9,070 ) (9,343 ) For the three-month period ended June 30, Personnel expenses 2020 2021 Wages and salaries (9,895 ) (13,192 ) Social charges on free shares and stock option grants — (100 ) Non-cash (4,651 ) (3,990 ) Total personnel expenses (14,546 ) (17,283 ) 3.3 Reportable segments Accounting policies Reportable segments are identified as components of the Group that have discrete financial information available for evaluation by the Chief Operating Decision Maker (“CODM”), for purposes of performance assessment and resource allocation. For the three-month and six-month • The Chief Executive Officer; • The Executive Vice President Strategic Initiatives; • The Executive Vice President Global Quality (until March 31, 2021); • The Senior Vice President Europe Technical Operations; • The Senior Vice President of US Manufacturing; • The Chief Scientific Officer; • The Chief Financial Officer; • The General Counsel; • The Chief Business Officer; • The Chief Regulatory & Compliance Officer; • The Chief Medical Officer; and • The Chief Human Resources Officer. We view our operations and manage our business in two operating and reportable segments that are engaged in the following activities: • Therapeutics: This segment is focused on the development (i) gene-edited allogeneic Chimeric Antigen Receptor T-cells • Plants: This segment focused on using an advanced plant-based technology platform to develop sustainable products and technologies, while leveraging partners and licensees to manage commercialization and the associated costs and risks. It corresponds to the activity of our U.S.-based majority-owned subsidiary, Calyxt, which is currently based in Roseville, Minnesota. There are inter-segment transactions between the two reportable segments, including allocation of corporate general and administrative expenses by Cellectis S.A. and allocation of research and development expenses to the reportable segments. With respect to corporate general and administrative expenses, Cellectis S.A. has provided Calyxt, with general sales and administrative functions, accounting and finance functions, investor relations, intellectual property, legal advice, human resources, communication and information technology under a Management Services Agreement. Effective with the end of the third quarter 2019, Calyxt has internalized nearly all of the services previously provided by Cellectis under this agreement. Under the Management Services Agreement, Cellectis S.A. charges Calyxt, in euros at cost plus a mark-up 12-month The intersegment revenues represent the transactions between segments. Intra-segment transactions are eliminated within a segment’s results and intersegment transactions are eliminated in consolidation as well as in key performance indicators by reportable segment. Information related to each reportable segment is set out below. Segment revenues and other income, Research and development expenses, Selling, general and administrative expenses, and Cost of revenue and other operating income and expenses, and Adjusted net income (loss) attributable to shareholders of Cellectis (which does not include non-cash Adjusted Net Income (Loss) attributable to shareholders of Cellectis S.A. is not a measure calculated in accordance with IFRS. Because Adjusted Net Income (Loss) attributable to shareholders of Cellectis excludes Non-cash non-cash The net income (loss) by segment includes the impact of the operations between segments while the intra-segment operations are eliminated. Details of key performance indicators by reportable segment for the six-month For the six-month period ended June 30, For the six-month period ended June 30, $ in thousands Plants Therapeutics Total Plants Therapeutics Total External revenues 4,670 48,323 52,993 16,716 20,061 36,777 External other income — 3,494 3,494 1,528 4,276 5,804 External revenues and other income 4,670 51,817 56,487 18,244 24,337 42,581 Cost of revenue (9,219 ) (1,207 ) (10,428 ) (18,706 ) (1,194 ) (19,899 ) Research and development expenses (5,388 ) (38,199 ) (43,587 ) (5,836 ) (56,503 ) (62,338 ) Selling, general and administrative expenses (11,774 ) (9,439 ) (21,213 ) (7,528 ) (10,691 ) (18,219 ) Other operating income and expenses (44 ) 131 86 7 482 489 Total operating expenses (26,426 ) (48,715 ) (75,142 ) (32,063 ) (67,905 ) (99,968 ) Operating income (loss) before tax (21,756 ) 3,102 (18,655 ) (13,818 ) (43,569 ) (57,387 ) Net financial gain (loss) (148 ) (487 ) (635 ) (584 ) 1,015 431 Net income (loss) (21,904 ) 2,615 (19,290 ) (14,402 ) (42,554 ) (56,956 ) Non controlling interests 7,069 — 7,069 5,169 — 5,169 Net income (loss) attributable to shareholders of Cellectis (14,835 ) 2,615 (12,221 ) (9,233 ) (42,554 ) (51,787 ) R&D non-cash 573 4,177 4,750 532 3,703 4,235 SG&A non-cash 1,879 1,667 3,546 (918 ) 916 (2 ) Adjustment of share-based compensation attributable to shareholders of Cellectis 2,452 5,844 8,296 (385 ) 4,619 4,233 Adjusted net income (loss) attributable to shareholders of Cellectis (12,383 ) 8,459 (3,924 ) (9,619 ) (37,935 ) (47,554 ) Depreciation and amortization (980 ) (3,212 ) (4,192 ) (1,218 ) (5,954 ) (7,173 ) Additions to tangible and intangible assets 355 29,832 30,187 308 11,020 11,327 Details of key performance indicators by reportable s e For the three-month period ended June 30, 2020 For the three-month period ended June 30, 2021 $ in thousands Plants Therapeutics Total reportable Plants Therapeutics Total reportable External revenues 2,293 607 2,900 11,728 (552 ) 11,176 External other income — 1,716 1,716 1,528 1,911 3,439 External revenues and other income 2,293 2,323 4,616 13,256 1,359 14,615 Cost of revenue (5,339 ) (487 ) (5,827 ) (11,337 ) (418 ) (11,754 ) Research and development expenses (2,754 ) (20,107 ) (22,862 ) (2,810 ) (28,336 ) (31,147 ) Selling, general and administrative expenses (5,311 ) (3,759 ) (9,070 ) (3,410 ) (5,933 ) (9,343 ) Other operating income and expenses (24 ) 135 111 31 118 150 Total operating expenses (13,429 ) (24,218 ) (37,647 ) (17,526 ) (34,569 ) (52,096 ) Operating income (loss) before tax (11,136 ) (21,895 ) (33,031 ) (4,270 ) (33,210 ) (37,481 ) Financial gain (loss) 185 (3,006 ) (2,821 ) (294 ) (3,836 ) (4,129 ) Net income (loss) (10,951 ) (24,901 ) (35,852 ) (4,564 ) (37,046 ) (41,610 ) Non controlling interests 3,589 — 3,589 1,691 — 1,691 Net income (loss) attributable to shareholders of Cellectis (7,362 ) (24,901 ) (32,263 ) (2,873 ) (37,046 ) (39,919 ) R&D non-cash stock-based expense attributable to shareholder of Cellectis (21 ) 1,749 1,728 271 2,398 2,669 SG&A non-cash stock-based expense attributable to shareholder of Cellectis 1,132 580 1,712 373 593 966 Adjustment of share-based compensation attributable to shareholders of Cellectis 1,112 2,329 3,441 644 2,991 3,635 Adjusted net income (loss) attributable to shareholders of Cellectis (6,250 ) (22,572 ) (28,823 ) (2,229 ) (34,055 ) (36,285 ) Depreciation and amortization (490 ) (1,657 ) (2,147 ) (614 ) (2,768 ) (3,382 ) Additions to tangible and intangible assets 207 16,003 16,210 39 4,688 4,727

Impairment tests

Impairment tests	6 Months Ended
	Jun. 30, 2021
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Impairment tests	Note 4. Impairment tests Our cash-generating units (“CGUs”) correspond to the operating/reportable segments: Therapeutics and Plants. No indicator of impairment has been identified for any intangible or tangible assets in the CGUs at the end of the three- or six-month

Right-of-use assets

Right-of-use assets	6 Months Ended
	Jun. 30, 2021
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Right-of-use assets	Note 5. Right-of-use Accounting policy Lease contracts recognition Lease contracts, as defined by IFRS 16 “Leases”, are recorded in the statement of consolidated financial position, which leads to the recognition of: • an asset representing a right of use of the asset leased during the lease term of the contract “right-of-use”; • a liability related to the payment obligation “lease debt”. Measurement of the right-of At the commencement date, the right-of-use • the amount of the initial measurement of the lease liability, to which is added, if applicable, any lease payments made at or before the commencement date, less any lease incentives received; • where relevant, any initial direct costs incurred by the lessee for the conclusion of the contract. These are incremental costs which would not have been incurred if the contract had not been concluded; and • estimated costs for restoration of the leased asset according to the terms of the contract. Following the initial recognition, the right-of-use Measurement of the lease liability At the commencement date, the lease liability is recognized for an amount equal to the present value of the lease payments over the lease term. Amounts involved in the measurement of the lease liability are: • fixed payments (including in-substance in-substance • variable lease payments that depend on an index or a rate, initially measured using the index or the rate in force at the lease commencement date; amounts expected to be payable by the lessee under residual value guarantees; and • payments of penalties for terminating the lease, if the lease term reflects the lessee exercising an option to terminate the lease. The lease liability is subsequently measured based on a process similar to the amortized cost method using the discount rate: • the liability is increased by the accrued interests resulting from the discounting of the lease liability, at the beginning of the lease period; and • payments made are deducted. The interest cost for the period as well as variable payments, not taken into account in the initial measurement of the lease liability and incurred over the relevant period are recognized as costs. In addition, the lease liability may be remeasured in the following situations: • the occurrence of a change in the lease term or a modification related to the assessment of the reasonably certain nature (or not) of the exercise of an option, • a remeasurement linked to residual value guarantees, or • the occurrence of an adjustment to the rates and indices according to which the rents are calculated when rent adjustments occur. COVID-19-Related On March 31, 2021, the IASB issued “COVID-19-Related COVID-19 The amount recognised in profit or loss for the reporting period to reflect changes in lease payments that arise from rent concessions to which the Group has applied the practical expedient in IFRS 16.46A is immaterial. There was no rent concession in the six-month Main contracts applicable Based on its analysis, the Group has identified lease contracts according to the standard concerning office buildings, laboratories, production facilities and storage facilities. For purposes of IFRS 16, the lease term reflects the Group’s reasonable expectation of the period during which the underlying asset will be used. The discount rate used to calculate the lease debt is determined, for each portfolio of assets, according to the incremental borrowing rate at the contract date. The incremental borrowing rate is the rate of interest that a lessee would have to pay to borrow over a similar term, and with a similar security, the funds necessary to obtain an asset of a similar value to the right-of-use The rental charges relating to short term and low value lease remains classified as leases expenses in operating expenses. Details of Right-of-use IFRS 16 “Leases” is applicable for annual periods beginning on or after January 1, 2019. The consequence of the application of this standard is to recognize a right of use and lease liability on the Statement of financial position. The breakdown of right-of-use Building Office and Total $ in thousands Net book value as of January 1, 2020 43,111 2,500 45,612 Additions to tangible assets 18,806 2,141 20,947 Depreciation expense (2,251 ) (647 ) (2,899 ) Translation adjustments (8 ) 16 9 Net book value as of June 30, 2020 59,659 4,010 63,669 Gross value at end of period 65,984 5,316 71,300 Accumulated depreciation and impairment at end of period (6,325 ) (1,306 ) (7,631 ) Net book value as of January 1, 2021 62,424 11,421 73,845 Additions (139 ) 5,666 5,527 Depreciation expense (2,882 ) (1,771 ) (4,653 ) Translation adjustments (584 ) (85 ) (668 ) Net book value as of June 30, 2021 58,819 15,232 74,050 Gross value at end of period 70,818 18,871 89,689 Accumulated depreciation at end of period (11,999 ) (3,639 ) (15,638 )

Property, plant and equipment

Property, plant and equipment	6 Months Ended
	Jun. 30, 2021
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Property, plant and equipment	Note 6. Property, plant and equipment Lands and Technical Fixtures, Assets Total $ in thousands Net book value as of January 1, 2020 3,330 3,160 2,435 14,787 23,712 Additions to tangible assets 487 271 294 29,103 30,156 Disposal of tangible assets — (9 ) — (0 ) (9 ) Reclassification 674 164 186 (1,025 ) (1 ) Depreciation expense (166 ) (633 ) (415 ) — (1,214 ) Translation adjustments 8 0 (0 ) 0 8 Net book value as of June 30, 2020 4,332 2,955 2,500 42,866 52,653 Gross value at end of period 8,994 14,364 4,628 42,866 70,851 Accumulated depreciation and impairment at end of period (4,661 ) (11,409 ) (2,128 ) (0 ) (18,198 ) Net book value as of January 1, 2021 16,765 4,436 3,171 47,301 71,673 Additions to tangible assets 2,778 2,127 1,046 5,376 11,327 Disposal of tangible assets (40 ) (72 ) — (59 ) (171 ) Reclassification 1,105 4,568 (860 ) (4,859 ) (47 ) Depreciation expense (1,056 ) (1,399 ) (329 ) — (2,784 ) Translation adjustments (333 ) (83 ) (31 ) (73 ) (520 ) Net book value as of June 30, 2021 19,218 9,577 2,997 47,686 79,478 Gross value at end of period 25,844 24,821 4,603 47,686 102,954 Accumulated depreciation and impairment at end of period (6,626 ) (15,245 ) (1,606 ) (0 ) (23,476 ) For the six-month period ended June 30, 2021, we continued our investments in research and development equipment in both the United States of America and France. The addition in tangible assets reflects improvements of Calyxt and Cellectis sites for $2.8 million and other equipment for $3.2 million ($2.1 million of technical equipment and $1.1 million of other equipment). Assets under construction as of June 30, 2021 primarily relates to Cellectis’ new raw materials manufacturing facility and offices in Paris ($2.0 million), and a new commercial manufacturing facility in Raleigh, North Carolina ($41.4 million), and the balance relates to capital expenditure in Cellectis’ New York office and in the Plants Segment. The assets put into service in 2021 mainly concern Cellectis’ Paris and Raleigh manufacturing facilities and offices for $3.8 million, with the remaining part relating to Calyxt.

Non-current financial assets

Non-current financial assets	6 Months Ended
	Jun. 30, 2021
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Non-current financial assets	Note 7. Non-current On February 12, 2021, Cellectis entered into an agreement with Cytovia Therapeutics, Inc. (“the Cytovia agreement”). The consideration to Cellectis includes a convertible note for $15 million issued by Cytovia to Cellectis upon the signature of the contract (which may be settled in cash or converted to equity of Cytovia under certain conditions). This convertible note does not bear interest. As of June 30, 2021, management has determined that the fair value of the note approximates its carrying value. The fair value measurement of the convertible note is categorized within Level 1. No credit loss is expected related to this convertible note. As of June 30, 2021, non-current

Trade receivables and other cur

Trade receivables and other current assets	6 Months Ended
	Jun. 30, 2021
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Trade receivables and other current assets	Note 8. Trade receivables and other current assets 8.1 Trade receivables As of December 31, As of June 30, $ in thousands Trade receivables 5,787 3,908 Valuation allowance (616 ) (31 ) Total net value of trade receivables 5,171 3,878 All trade receivables have payment terms of less than one year. The trade receivables as of June 30, 2021 are mainly due to Calyxt’s seed and grain crop sales. 8.2 Subsidies receivables As of December 31, As of June 30, $ in thousands Research tax credit 10,703 5,654 Total subsidies receivables 10,703 5,654 Research tax credit receivables as of June 30, 2021 include the accrual for a French research tax credit related to 2021 for $4.2 million, and to previous periods for $1.3 million. The remaining amount relates to refundable tax credits in the United States. During December 2018, the French Tax Authority initiated an audit related to the 2014, 2015, 2016 and 2017 French research tax credits. Based on our current evaluation of the status of the audit, we do not believe that a provision should be recorded as of June 30, 2021 8.3 Other current assets As of December 31, As of June 30, $ in thousands VAT receivables 3,093 2,147 Prepaid expenses and other prepayments 14,113 13,431 Tax and social receivables 227 270 Deferred expenses and other current assets 12,210 885 Total other current assets 29,643 16,733 Prepaid expenses and other prepayments primarily include advances to our sub-contractors During the year ended December 31, 2020, and the six-month As of December 31, 2020, deferred expenses and other current assets mainly relates to a $6.2 million receivable following Cellectis’ employees’ option exercises which was subsequently received, a Calyxt broker receivable and certain down payments to suppliers for $2.7 million, as well as a right of $3.0 million to obtain equipment at our Raleigh facility which generated an equivalent financial liability As of June 30, 2021, deferred expenses and other current assets mainly relates to down payments to suppliers for Calyxt and Cellectis Paris. All equipment at our Raleigh facility has been received. As of December 31, 2020, and as of June 30, 2021, tax and social receivables relate mainly to social charges on personnel expenses.

Current financial assets and Ca

Current financial assets and Cash and cash equivalents	6 Months Ended
	Jun. 30, 2021
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Current financial assets and Cash and cash equivalents	Note 9. Current financial assets and Cash and cash equivalents As of December 31, 2020 Carrying Unrealized Estimated fair $ in thousands Current financial assets 27,091 — 27,091 Cash and cash equivalents 241,148 — 241,148 Current financial assets and cash and cash equivalents 268,239 — 268,239 As of June 30, 2021 Carrying Unrealized Estimated fair $ in thousands Current financial assets 3,393 — 3,393 Cash and cash equivalents 248,226 — 248,226 Current financial assets and cash and cash equivalents 251,619 — 251,619 9.1 Current financial assets Current financial assets include current restricted cash and other current financial assets. As of June 30, 2021, restricted cash consists of: i. deposit to secure commitment to supplier regarding the manufacturing facility construction for $3 million classified as short-term restricted cash included within current financial assets, and ii. deposits to secure a Calyxt furniture and equipment sale-leaseback for $1.0 million of which $0.4 million are classified as short-term restricted cash included within current financial assets. Other current financial assets are measured at fair value through profit or loss and are classified as follows within the fair value hierarchy: Instruments classified under level 1 are measured with reference to quoted prices in active markets; they consist of corporate debt securities and commercial paper. Their nominal value and their fair value amounted to $0.0 million in each case as of June 30, 2021 and to $11.7 million as of December 31, 2020. 9.2 Cash and cash equivalents As of December 31, As of June 30, $ in thousands Cash and bank accounts 164,586 192,661 Money market funds 13,977 13,971 Fixed bank deposits 62,585 41,594 Total cash and cash equivalents 241,148 248,226 Money market funds earn interest and are refundable overnight. Fixed bank deposits have fixed terms that are less than three months or are readily convertible to a known amount of cash.

Financial liabilities

Financial liabilities	6 Months Ended
	Jun. 30, 2021
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Financial liabilities	Note 10. Financial liabilities 10.1 Detail of financial liabilities As of December 31, As of June 30, $ in thousands Lease debts 75,764 75,763 State Guaranteed loan « PGE » 22,701 22,137 PPP loan 1,518 — Other non-current 4,617 1,339 Total non-current non-current 104,600 99,238 Lease debts 6,696 7,691 Total current financial liabilities 6,696 7,691 Trade payables 24,609 28,254 Other current liabilities 19,127 13,681 Total Financial liabilities 155,032 148,864 As of June 30, 2021, the other non-current PPP loan corresponds to Calyxt’s obtention of a $1.5 million paycheck protection program (PPP) loan under the U.S. Coronavirus Aid, Relief and Economic Security (CARES) Act, for which Calyxt has obtained full forgiveness on April 8, 2021, from the Small Business Administration, which administers the PPP loan program, and recognized as other income in the three months ended June 30, 2021. State Guaranteed loan « PGE » corresponds to includes Cellectis’ obtention of an €18.5 million (or $22.0 million using exchange rate as of June 30, 2021) loan from a bank syndicate formed with HSBC, Société Générale, Banque Palatine and Bpifrance in the form of a state-guaranteed loan (Prêt Garanti par l’Etat) (the “PGE“). Initiated by the French Government to support companies during the COVID-19 10.2 Due dates of the financial liabilities Balance as of June 30, 2021 Book value Less than One One to Five More than $ in thousands Lease debts 83,454 7,691 34,026 41,736 Other financial liabilities 23,475 134 22,348 993 Financial liabilities 106,929 7,825 56,374 42,730 Trade payables 28,254 28,254 — — Other current liabilities 13,681 13,681 — — Total financial liabilities 148,864 49,760 56,374 42,730

Other current liabilities

Other current liabilities	6 Months Ended
	Jun. 30, 2021
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Other current liabilities	Note 11. Other current liabilities As of December 31, As of June 30, $ in thousands VAT Payables 81 201 Accruals for personnel related expenses 12,969 9,565 Other 6,077 3,915 Total 19,127 13,681 Accruals for personnel are related to annual bonuses, vacations accruals and social expenses on stock options. The decrease in accruals for personnel related expenses between December 31, 2020 and June 30, 2021 is mainly explained by yearly bonus payments which occurred in February 2021. The decrease in other between December 31, 2020 and June 30, 2021, is mainly driven by fixed assets accruals.

Deferred revenues and contract

Deferred revenues and contract liabilities	6 Months Ended
	Jun. 30, 2021
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Deferred revenues and contract liabilities	Note 12. Deferred revenues and contract liabilities As of December 31, 2020 As of June 30, 2021 $ in thousands Deferred revenues and contract liabilities 452 423 Others — — Total Deferred revenue and contract liabilities 452 423

Share capital and premium relat

Share capital and premium related to the share capitals	6 Months Ended
	Jun. 30, 2021
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Share capital and premium related to the share capitals	Note 13. Share capital and premium related to the share capitals Nature of the Transactions Share Share Number of Nominal $ in thousands (except number of shares) in $ Balance as of January 1, 2020 2,767 843,478 42,465,669 0.05 Capital Increase 1 — 20,464 — Non-cash — 5,844 — — Other movements — — — — Balance as of June 30, 2020 2,768 849,322 42,486,133 0.05 Balance as of January 1, 2021 2,785 863,911 42,780,186 0.05 Capital increase (ATM) 146 47,688 2,415,630 — Exercise of share warrants, employee warrants and stock options 16 5,702 265,494 — Non-cash — 4,233 — — Transaction costs — (910 ) — — Other movements — (34 ) — — Balance as of June 30, 2021 2,947 920,591 45,461,310 0.05 Capital evolution during the six-month • During the six-month Cellectis’At-The-Market • During the six-month

Non-cash share-based compensati

Non-cash share-based compensation	6 Months Ended
	Jun. 30, 2021
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Non-cash share-based compensation	Note 14. Non-cash 14.1 Detail of Cellectis equity awards Holders of vested Cellectis stock options and warrants are entitled to exercise such options and warrants to purchase Cellectis ordinary shares at a fixed exercise price established at the time such options and warrants are granted during their useful life. For stock options and warrants, we estimate the fair value of each option on the grant date or other measurement date if applicable using a Black-Scholes option-pricing model, which requires us to make predictive assumptions regarding future stock price volatility, employee exercise behavior, dividend yield, and the forfeiture rate. We estimate our future stock price volatility based on Cellectis historical closing share prices over the expected term period. Our expected term represents the period of time that options granted are expected to be outstanding determined using the simplified method. The risk-free interest rate for periods during the expected term of the options is based on the French government securities with maturities similar to the expected term of the options in effect at the time of grant. We have never declared or paid any cash dividends and do not presently plan to pay cash dividends in the foreseeable future. Consequently, we used an expected dividend yield of zero. Options may be priced at 100 percent or more of the fair market value on the date of grant, and generally vest over four years after the date of grant. Options generally expire within ten years after the date of grant. Stock Options The weighted-average fair values of stock options granted and the assumptions used for the Black-Scholes option pricing model were as follows: 2020 2021 Weighted-Average fair values of stock options granted 7.00€ 5.76€ Assumptions: Risk-free interest rate 0.00% 0.00% Share entitlement per options 1 1 Exercise price 8.27€ - 15.84€ 14.36€ - 19.44€ Grant date share fair value 9.14€ - 15.76€ 12.69€ - 16.54€ Expected volatility 61.3% - 62.8% 59.9% - 60.1% Expected term (in years) 6.15 6.15 Vesting conditions Service Service Vesting period Graded Graded Information on stock option activity follows: Options Weighted- Options Weighted- Remaining Balance as of December 31, 2019 6,922,172 26.30 € 9,672,382 24.22 € 6.8y Granted — — 479,000 12.54 € Exercised — — (291,053 ) 17.86 € Forfeited or Expired — — (373,672 ) 20.61 € Balance as of December 31, 2020 8,002,398 25.28 € 9,486,657 23.97 € 5.9y Granted — — 955,485 19.32 Exercised — — (253,494 ) 18.49 € Forfeited or Expired — — (535,638 ) 19.81 € Balance as of June, 2021 7,750,761 25.34 € 9,653,010 23.88 € 5.8y Share-based compensation expense related to stock option awards was $1.6 million and $5.5 million for the six-month Warrants No Warrants (or “Bons de Souscriptions d’Actions” or “BSA”) have been granted during the periods presented. Information on warrants activity follows: Warrants Weighted- Warrants Weighted- Remaining Balance as of December 31, 2019 852,260 35.35 € 918,927 35.12 € 6.9y Granted — — — — Exercised — — (19,702 ) 8.28 € Forfeited or Expired — — — — Balance as of December 31, 2020 899,225 27.15 € 899,225 27.15 € 5.3y Granted — — — — Exercised — — (3,000 ) 18.68 € Forfeited or Expired — — — — Balance as of June 30, 2021 896,225 27.18 € 896,225 27.18 € 4.9y There was no share-based compensation expense related to warrants awards for the six-months Free shares The free shares granted prior to 2018 are subject to a two two four The free shares granted in 2018 and after are subject to a one one two Information on free shares activity follows: Number of Free shares Weighted-Average Grant Unvested balance at December 31, 2019 67,000 13.98 € Granted (1) 591,685 20.10 € Vested (3,000 ) 23.84 € Cancelled (26,035 ) 16.45 € Unvested balance at December 31, 2020 629,650 19.59 € Granted 332,041 12.78 € Vested (9,000 ) 17.45 € Cancelled (90,640 ) 16.32 € Unvested balance at June 30, 2021 862,051 17.33 € (1) 423,285 free shares have been granted in October 2020 under the Amended Second Free Shares 2018 Plan and are under non-market three 330,041 three 103,000 non-market The fair value of free shares corresponds to the grant date share fair value. We have never declared or paid any cash dividends and do not presently plan to pay cash dividends in the foreseeable future. Consequently, we used an expected dividend yield of zero in determining fair value. Share-based compensation expense related to free shares awards was $3.0 million and $0.1 million for the six-month 14.2 Detail of Calyxt equity awards Stock Options The estimated fair values of stock options granted and the assumptions used for the Black-Scholes option pricing model were as follows: 2020 2021 Weighted-Average fair values of stock options granted $5.19 $4.54 Assumptions: Risk-free interest rate 1.7% 0.6% - 1.1% Share entitlement per options 1 1 Expected volatility 77.4% 80.1% - 82.0% Expected term (in years) 6.9 5.5 - 6.5 Vesting conditions Service Service Vesting period Graded Graded Calyxt estimates the fair value of each option on the grant date or other measurement date if applicable using a Black-Scholes option-pricing model, which requires Calyxt to make predictive assumptions regarding future stock price volatility, employee exercise behavior, dividend yield, and the forfeiture rate. Calyxt estimates its future stock price volatility using the historical volatility of comparable public companies over the expected term of the option. Calyxt’s expected term represents the period of time that options granted are expected to be outstanding determined using the simplified method. The risk-free interest rate for periods during the expected term of the options is based on the U.S. Treasury zero-coupon Calyxt has not paid and does not expect to pay dividends for the foreseeable future. Options may be priced at 100 percent or more of the fair market value on the date of grant, and generally vest over six years after the date of grant. Options generally expire within ten years after the date of grant. Certain awards granted before Calyxt’s IPO contained accelerated vesting provisions if certain events occurred as defined in the option agreement. Information on stock option activity follows: Options Weighted- Options Weighted- Remaining Balance as of December 31, 2019 1,789,567 $ 8.73 4,481,359 $ 11.73 6.8y Granted 887,765 $ 4.67 Exercised (58,575 ) $ 3.60 Forfeited or Expired (689,376 ) $ 12.89 Balance as of December 31, 2020 2,347,663 $ 10.15 4,621,173 $ 10.30 6.2y Granted 456,959 $ 5.71 Exercised (61,372 ) $ 3.70 Forfeited or Expired (550,110 ) $ 10.57 Balance as of June 30, 2021 2,412,501 $ 10.49 4,466,650 $ 9.89 5.8y Stock-based compensation expense related to stock option awards was an expense of $0.4 million, compared to an expense of $2.4 million for the six-month Restricted Stock Units Units settled in stock subject to a restricted period may be granted to key employees under the 2017 Omnibus Plan. Restricted stock units generally vest and become unrestricted over five years after the date of grant. Information on restricted stock unit activity follows: Number of Restricted Weighted-Average Unvested balance at December 31, 2020 547,807 $ 9.49 Granted 234,504 $ 5.61 Vested (69,323 ) $ 9.25 Cancelled (133,348 ) $ 12.49 Unvested balance at June 30, 2021 579,640 $ 7.26 The fair value of restricted stock units corresponds to the grant date share fair value. Calyxt has not paid and does not expect to pay dividends for the foreseeable future. Share-based compensation expense related to restricted stock units awards was a gain of $0.6 million due to options forfeiture, compared to an expense of $1.0 million for the six-months Performance Stock Unit In June 2019, Calyxt granted performance stock units, which carry a market condition based on Calyxt share price. These awards contain a continuous service period of three years, the performance period, from the date of grant, followed by a restricted period of two years if the shares are issued following the performance period during which the grantee is required to provide continuous service and the awarded shares must be held by the grantee until the end of the period. The number of shares of common stock delivered following the performance period depends upon the change in Calyxt share price during the performance period. Calyxt granted a targeted 311,667 performance stock units. The performance criteria allow for the actual payout to be between zero and 120 percent of target. The fair value of the performance stock units and the assumptions used for the Monte Carlo simulation were as follows:​​​​​​​ Date of grant 06/28/2019 Estimated fair values of performance stock units granted $ 7.06 Assumptions: Risk-free interest rate 1.71 % Expected volatility 75.0 % Expected term (in years) 3.0 years Information on performance stock unit activity follows: Number of Weighted- Unvested balance at December 31, 2020 311,667 $ 7.06 Granted — — Vested — — Cancelled (166,667 ) Unvested balance at June 30, 2021 145,000 $ 7.06 Share-based compensation expense related to performance stock units awards was a gain of $0.3 million due to options forfeiture, compared to an expense of $0.2 million for the six-month

Earnings per share

Earnings per share	6 Months Ended
	Jun. 30, 2021
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Earnings per share	Note 15. Earnings per share 15.1 For the six-month For the six-month period ended June 30, 2020 2021 Net income (loss) attributable to shareholders of Cellectis ($ in thousands) (12,221 ) (51,787 ) Adjusted weighted average number of outstanding shares, used to calculate both basic and diluted net result per share 42,469,080 44,163,914 Basic / Diluted net income (loss) per share attributable to shareholders of Cellectis Basic net income (loss) attributable to shareholders of Cellectis per share ( $ /share) (0.29 ) (1.17 ) Diluted net income (loss) attributable to shareholders of Cellectis per share ( $ /share) (0.29 ) (1.17 ) When we have adjusted net loss, in accordance with IFRS, we use the Weighted average number of outstanding shares, basic to compute the diluted adjusted net income (loss) attributable to shareholders of Cellectis ($/share). When we have adjusted net income, in accordance with IFRS, we use the weighted average number of outstanding shares, diluted to compute the diluted adjusted net income (loss) attributable to shareholders of Cellectis ($/share) 15.2 For the three-month periods ended June 30 For the three-month period ended 2020 2021 Net income (loss) attributable to shareholders of Cellectis ($ in thousands) (32,263 ) (39,919 ) Adjusted weighted average number of outstanding shares, used to calculate both basic and diluted net result per share 42,472,490 45,461,310 Basic / Diluted net income (loss) per share attributable to shareholders of Cellectis per share ($ / share) Basic net income (loss) per share ($ /share) (0.76 ) (0.88 ) Diluted net income (loss) per share ($ /share) (0.76 ) (0.88 ) When we have adjusted net loss, in accordance with IFRS, we use the Weighted average number of outstanding shares, basic to compute the diluted adjusted net income (loss) attributable to shareholders of Cellectis ($/share). When we have adjusted net income, in accordance with IFRS, we use the weighted average number of outstanding shares, diluted to compute the diluted adjusted net income (loss) attributable to shareholders of Cellectis ($/share)

Provisions

Provisions	6 Months Ended
	Jun. 30, 2021
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Provisions	Note 16. Provisions 31/12/2020 Additions Amounts Reversals OCI 30/06/2021 $ in thousands Pension 4,010 299 — — (699 ) 3,610 Loss on contract — — — — — — Employee litigation and severance 560 30 (101 ) (84 ) (15 ) 391 Commercial litigation 571 901 (194 ) (246 ) (25 ) 1,006 Total 5,141 1,230 (296 ) (330 ) (739 ) 5,007 During the six-month The amounts used and reversed during the period mainly relate (i) the settlement of employee litigation for $0.2 million and (ii) the update of a commercial litigation for $(0.4) million.

Commitments

Commitments	6 Months Ended
	Jun. 30, 2021
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Commitments	Note 17. Commitments As of June 30, 2021 Total Less than 1 1 - 3 3 - 5 More than 5 $ in thousands License agreements 18,345 1,530 3,060 3,060 10,695 Manufacturing agreements 947 930 18 — — Clinical & R&D agreements 288 234 54 — — Construction agreements 1,687 1,687 — — — IT licensing agreements 1,335 445 890 — — Other agreements 6,839 6,839 — — — Total commitments 29,442 11,665 4,022 3,060 10,695 Obligations under the terms of lease agreements Almost all of our lease agreement are accounted for under IFRS 16 and thereby are presented in the statement of consolidated financial position. The commitments related to operating leases exempted from IFRS 16 application are immaterial. Obligations under the terms of license agreements We have entered into various license agreements with third parties that subject us to certain fixed license fees, as well as fees based on future events, such as research and sales milestones. We also have collaboration agreements whereby we are obligated to pay royalties and milestone payments based on future events that are uncertain and therefore they are not included in the table above. Obligations under the terms of manufacturing agreements We have manufacturing agreements whereby we are obligated to pay for services rendered in the next 12 months regarding our products UCART123, UCARTCS1 and UCART22. Obligations under the terms of Clinical & Research agreements We have entered into clinical and research agreements where we are obligated to pay for services to be provided regarding our research collaboration agreements, clinical trials and translational research projects. Obligations under the terms of Construction agreements We have entered into a construction agreement regarding our manufacturing facility based in Raleigh, North Carolina, where we committed to pay for construction work. Obligations under the terms of other agreements Calyxt has entered into seed and grain production agreements (Forward Purchase Contracts) with seed producers and growers. Calyxt announced in December 2020 that Archer Daniels Midland has committed to purchase over four million bushels of Calyxt’s grain, which includes all the 2020 soybean crop, which Calyxt will purchase from growers between January 1, 2021 and August 31, 2021. Calyxt expects to sell that grain throughout 2021 and no later than December 31, 2021. Calyxt expects to sell the remaining grain to Archer Daniels Midland at market prices, and as a result, Calyxt will continue to hedge fixed price grain inventories and fixed price Forward Purchase Contracts to mitigate the risk changing market prices may have on Calyxt’s margins. As of June 30, 2021, Calyxt has non-cancelable The seed contracts often require Calyxt to pay prices for the seed produced at an exchange-traded price of grain plus a premium with the seed grower having the option to fix their price with Calyxt throughout the term of the agreement. The grower contracts are linked to a commodity futures market prices with the grain grower having the option to fix their price with Calyxt throughout the term of the agreement. The grain grower contracts allow for delivery of grain to Calyxt at harvest if so specified when the agreement is executed, otherwise delivery occurs on a date that Calyxt elects through August 31 of the following year. In all periods presented, we considered Forward Purchase Contracts as normal purchases and not derivatives. Any mark-to-market As of June 30, 2021, Calyxt has $1.0 million of unrealized commodity derivative losses from hedging contracts sold to convert their fixed price grain inventories and fixed price Forward Purchase Contracts to floating prices. As of June 30, 2021, Calyxt held commodity contracts with a notional amount of $8.0 million.

Subsequent events

Subsequent events	6 Months Ended
	Jun. 30, 2021
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Subsequent events	Note 18. Subsequent events None

Accounting principles (Policies

Accounting principles (Policies)	6 Months Ended
	Jun. 30, 2021
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Basis for preparation	2.1 Basis for preparation The Interim Consolidated Financial Statements of Cellectis as of, and for the three- and six-month The Interim Consolidated Financial Statements are presented in U.S. dollars. See Note 2.2. The Interim Consolidated Financial Statements as of, and for the three- and six-month The Interim Consolidated Financial Statements as of and for the three- and six-month IFRS include International Financial Reporting Standards (“IFRS”), International Accounting Standards (“the IAS”), as well as the interpretations issued by the Standards Interpretation Committee (“the SIC”), and the International Financial Reporting Interpretations Committee (“IFRIC”). Application of new or amended accounting standards or new amendments The following pronouncements and related amendments have been adopted by us from January 1, 2021 but had no significant impact on the Interim Consolidated Financial Statements: • Interest Rate Benchmark Reform – Phase 2: Amendments to IFRS 9, IAS 39, IFRS 7, IFRS 4 and IFRS 16. The amendments provide temporary reliefs which address the financial reporting effects when an interbank offered rate (IBOR) is replaced with an alternative nearly risk-free interest rate (RFR). • Amendments to IFRS 16 Leases: Covid-19-Related Accounting standards, interpretations and amendments issued but not yet effective The following pronouncements and related amendments are applicable for accounting periods beginning after January 1, 2022. We do not anticipate that the adoption of these pronouncements and amendments will have a material impact on our results of operations, financial position or cash flows: • Amendments to IAS 37 – Onerous Contracts: Cost of Fulfilling a Contract (Effective for the accounting periods as of January 1, 2022) • Amendments to IAS 16 – Property, Plant and Equipment: Proceeds before Intended Use (Effective for the accounting periods as of January 1, 2022) • Amendments to IFRS 3 – Reference to the Conceptual Framework (Effective for the accounting periods as of January 1, 2022) • Amendments to IAS 8 – Definition of Accounting Estimates (issued on 12 February 2021 and Effective for the accounting periods as of January 1, 2023) • Amendments to IAS 12 – Income Taxes: Deferred Tax related to Assets and Liabilities arising from a Single Transaction (issued on 8 May 2021 and Effective for the accounting periods as of January 1, 2023)
Currency of the financial statements	2.2 Currency of the financial statements The Interim Consolidated Financial Statements are presented in U.S. dollars, which differs from the functional currency of Cellectis, which is the euro. We believe that this presentation enhances the comparability with peers, which primarily present their financial statements in U.S. dollars. All financial information (unless indicated otherwise) is presented in thousands of U.S. dollars. The statements of financial position of consolidated entities having a functional currency different from the U.S. dollar are translated into U.S. dollars at the closing exchange rate (spot exchange rate at the statement of financial position date) and the statements of operations, statements of comprehensive income (loss) and statements of cash flows of such consolidated entities are translated at the average period to date exchange rate. The resulting translation adjustments are included in equity under the caption “Accumulated other comprehensive income (loss)” in the Statements of Changes in Shareholders’ Equity.
Consolidated entities and non-controlling interests	2.3 Consolidated entities and non-controlling Accounting policy We control all the legal entities included in the consolidation. An investor controls an investee when the investor is exposed to variable returns from its involvement with the investee and has the ability to affect those returns through its power over the investee. Control requires power, exposure to variability of returns and a linkage between the two. To have power, the investor needs to have existing rights that give it the current ability to direct the relevant activities that significantly affect the investee’s returns. In order to ascertain control, potential voting rights which are substantial are taken into consideration. Consolidation of a subsidiary begins when the Group obtains control over the subsidiary and ceases when the Group loses control of the subsidiary. All intra-Group assets and liabilities, equity, income, expenses and cash flows relating to transactions between members of the Group are eliminated in full in the consolidation. Consolidated entities For the six-month As of June 30, 2021, Cellectis S.A. owns 100% of Cellectis, Inc., which owns 100% of Cellectis Biologics, Inc., and approximately 64.4% of Calyxt’s outstanding shares of common stock. Non-controlling Non-controlling non-controlling follow-on
Reportable segments	3.3 Reportable segments Accounting policies Reportable segments are identified as components of the Group that have discrete financial information available for evaluation by the Chief Operating Decision Maker (“CODM”), for purposes of performance assessment and resource allocation. For the three-month and six-month • The Chief Executive Officer; • The Executive Vice President Strategic Initiatives; • The Executive Vice President Global Quality (until March 31, 2021); • The Senior Vice President Europe Technical Operations; • The Senior Vice President of US Manufacturing; • The Chief Scientific Officer; • The Chief Financial Officer; • The General Counsel; • The Chief Business Officer; • The Chief Regulatory & Compliance Officer; • The Chief Medical Officer; and • The Chief Human Resources Officer. We view our operations and manage our business in two operating and reportable segments that are engaged in the following activities: • Therapeutics: This segment is focused on the development (i) gene-edited allogeneic Chimeric Antigen Receptor T-cells • Plants: This segment focused on using an advanced plant-based technology platform to develop sustainable products and technologies, while leveraging partners and licensees to manage commercialization and the associated costs and risks. It corresponds to the activity of our U.S.-based majority-owned subsidiary, Calyxt, which is currently based in Roseville, Minnesota. There are inter-segment transactions between the two reportable segments, including allocation of corporate general and administrative expenses by Cellectis S.A. and allocation of research and development expenses to the reportable segments. With respect to corporate general and administrative expenses, Cellectis S.A. has provided Calyxt, with general sales and administrative functions, accounting and finance functions, investor relations, intellectual property, legal advice, human resources, communication and information technology under a Management Services Agreement. Effective with the end of the third quarter 2019, Calyxt has internalized nearly all of the services previously provided by Cellectis under this agreement. Under the Management Services Agreement, Cellectis S.A. charges Calyxt, in euros at cost plus a mark-up 12-month The intersegment revenues represent the transactions between segments. Intra-segment transactions are eliminated within a segment’s results and intersegment transactions are eliminated in consolidation as well as in key performance indicators by reportable segment. Information related to each reportable segment is set out below. Segment revenues and other income, Research and development expenses, Selling, general and administrative expenses, and Cost of revenue and other operating income and expenses, and Adjusted net income (loss) attributable to shareholders of Cellectis (which does not include non-cash Adjusted Net Income (Loss) attributable to shareholders of Cellectis S.A. is not a measure calculated in accordance with IFRS. Because Adjusted Net Income (Loss) attributable to shareholders of Cellectis excludes Non-cash non-cash The net income (loss) by segment includes the impact of the operations between segments while the intra-segment operations are eliminated.
Right-of-use assets	Accounting policy Lease contracts recognition Lease contracts, as defined by IFRS 16 “Leases”, are recorded in the statement of consolidated financial position, which leads to the recognition of: • an asset representing a right of use of the asset leased during the lease term of the contract “right-of-use”; • a liability related to the payment obligation “lease debt”. Measurement of the right-of At the commencement date, the right-of-use • the amount of the initial measurement of the lease liability, to which is added, if applicable, any lease payments made at or before the commencement date, less any lease incentives received; • where relevant, any initial direct costs incurred by the lessee for the conclusion of the contract. These are incremental costs which would not have been incurred if the contract had not been concluded; and • estimated costs for restoration of the leased asset according to the terms of the contract. Following the initial recognition, the right-of-use Measurement of the lease liability At the commencement date, the lease liability is recognized for an amount equal to the present value of the lease payments over the lease term. Amounts involved in the measurement of the lease liability are: • fixed payments (including in-substance in-substance • variable lease payments that depend on an index or a rate, initially measured using the index or the rate in force at the lease commencement date; amounts expected to be payable by the lessee under residual value guarantees; and • payments of penalties for terminating the lease, if the lease term reflects the lessee exercising an option to terminate the lease. The lease liability is subsequently measured based on a process similar to the amortized cost method using the discount rate: • the liability is increased by the accrued interests resulting from the discounting of the lease liability, at the beginning of the lease period; and • payments made are deducted. The interest cost for the period as well as variable payments, not taken into account in the initial measurement of the lease liability and incurred over the relevant period are recognized as costs. In addition, the lease liability may be remeasured in the following situations: • the occurrence of a change in the lease term or a modification related to the assessment of the reasonably certain nature (or not) of the exercise of an option, • a remeasurement linked to residual value guarantees, or • the occurrence of an adjustment to the rates and indices according to which the rents are calculated when rent adjustments occur. COVID-19-Related On March 31, 2021, the IASB issued “COVID-19-Related COVID-19 The amount recognised in profit or loss for the reporting period to reflect changes in lease payments that arise from rent concessions to which the Group has applied the practical expedient in IFRS 16.46A is immaterial. There was no rent concession in the six-month Main contracts applicable Based on its analysis, the Group has identified lease contracts according to the standard concerning office buildings, laboratories, production facilities and storage facilities. For purposes of IFRS 16, the lease term reflects the Group’s reasonable expectation of the period during which the underlying asset will be used. The discount rate used to calculate the lease debt is determined, for each portfolio of assets, according to the incremental borrowing rate at the contract date. The incremental borrowing rate is the rate of interest that a lessee would have to pay to borrow over a similar term, and with a similar security, the funds necessary to obtain an asset of a similar value to the right-of-use The rental charges relating to short term and low value lease remains classified as leases expenses in operating expenses.

Information concerning the Gr_2

Information concerning the Group's Consolidated Operations (Tables)	6 Months Ended
	Jun. 30, 2021
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Revenues By Country of Origin and Other Income	Revenues by country of origin and other income For the six-month period ended June 30, 2020 2021 $ in thousands From France 48,323 20,061 From USA (1) 4,670 16,716 Revenues 52,993 36,777 Research tax credit 3,573 4,272 Subsidies and other (2) (79 ) 1,532 Other income 3,494 5,804 Total revenues and other income 56,487 42,581 (1) Revenues from USA concern Calyxt only. (2) As of June 30, 2021, this only includes Calyxt’s PPP loan, which is now forgiven and recognized as other income such as disclosed in note 10.1. For the three-month period ended June 30, 2020 2021 $ in thousands From France (3) 607 (552 ) From USA (1) 2,293 11,728 Revenues 2,900 11,176 Research tax credit 1,725 1,909 Subsidies and other (2) (10 ) 1,530 Other income 1,716 3,439 Total revenues and other income 4,616 14,615 (1) Revenues from USA concern Calyxt only. (2) As of June 30, 2021, this only includes Calyxt’s PPP loan, which is now forgiven and recognized as other income such as disclosed in note 10.1. (3) As of June 30, 2021, the negative impact corresponds to Cytovia’s convertible note revaluation for the three months ended March 31, 2021 which has been reclassified to financial result in the three months ended June 30, 2021.
Revenues by Nature	Revenues by nature For the six-month period ended June 30, 2020 2021 $ in thousands Recognition of previously deferred upfront payments 19,535 — Other revenues 27,536 20,014 Collaboration agreements 47,071 20,014 Licenses 1,233 — Products & services 4,689 16,763 Total revenues 52,993 36,777 For the three-month period ended June 30, 2020 2021 $ in thousands Recognition of previously deferred upfront payments — — Other revenues (1) 110 (551 ) Collaboration agreements 110 (551 ) Licenses (1) 466 (48 ) Products & services 2,324 11,775 Total revenues 2,900 11,176 (1) As of June 30, 2021, the negative impact corresponds to Cytovia’s convertible note revaluation for the three months ended March 31, 2021 which has been reclassified to financial result in the three months ended June 30, 2021.
Details of Operating Expenses by Nature	For the six-month period ended June 30, 2020 2021 Cost of goods sold (9,204 ) (18,706 ) Royalty expenses (1,223 ) (1,194 ) Cost of revenue (10,428 ) (19,899 ) For the six-month Research and development expenses 2020 2021 Wages and salaries (13,276 ) (20,863 ) Social charges on stock option grants — (845 ) Non-cash (5,014 ) (4,530 ) Personnel expenses (18,290 ) (26,237 ) Purchases and external expenses (21,743 ) (30,897 ) Other (3,555 ) (5,204 ) Total research and development expenses (43,587 ) (62,338 ) For the six-month Selling, general and administrative expenses 2020 2021 Wages and salaries (7,890 ) (9,183 ) Social charges on stock option grants — (350 ) Non-cash (4,413 ) 509 Personnel expenses (12,302 ) (9,024 ) Purchases and external expenses (6,980 ) (6,419 ) Other (1,931 ) (2,776 ) Total selling, general and administrative expenses (21,213 ) (18,219 ) For the six-month period ended June 30, Personnel expenses 2020 2021 Wages and salaries (21,165 ) (30,046 ) Social charges on stock option grants — (1,195 ) Non-cash (9,427 ) (4,020 ) Total personnel expenses (30,592 ) (35,261 ) For the three-month period ended June 30, 2020 2021 Cost of goods sold (5,320 ) (11,375 ) Royalty expenses (507 ) (380 ) Cost of revenue (5,827 ) (11,754 ) For the three-month period ended June 30, Research and development expenses 2020 2021 Wages and salaries (6,790 ) (9,986 ) Social charges on free shares and stock option grants — (84 ) Non-cash (2,410 ) (2,819 ) Personnel expenses (9,200 ) (12,888 ) Purchases and external expenses (11,775 ) (15,845 ) Other (1,887 ) (2,413 ) Total research and development expenses (22,862 ) (31,147 ) For the three-month period ended June 30, Selling, general and administrative expenses 2020 2021 Wages and salaries (3,105 ) (3,206 ) Social charges on free shares and stock option grants — (17 ) Non-cash (2,240 ) (1,172 ) Personnel expenses (5,345 ) (4,395 ) Purchases and external expenses (2,653 ) (3,600 ) Other (1,072 ) (1,348 ) Total selling, general and administrative expenses (9,070 ) (9,343 ) For the three-month period ended June 30, Personnel expenses 2020 2021 Wages and salaries (9,895 ) (13,192 ) Social charges on free shares and stock option grants — (100 ) Non-cash (4,651 ) (3,990 ) Total personnel expenses (14,546 ) (17,283 )
Summary of Key Performance Indicators by Reportable Segments	Details of key performance indicators by reportable segment for the six-month For the six-month period ended June 30, For the six-month period ended June 30, $ in thousands Plants Therapeutics Total Plants Therapeutics Total External revenues 4,670 48,323 52,993 16,716 20,061 36,777 External other income — 3,494 3,494 1,528 4,276 5,804 External revenues and other income 4,670 51,817 56,487 18,244 24,337 42,581 Cost of revenue (9,219 ) (1,207 ) (10,428 ) (18,706 ) (1,194 ) (19,899 ) Research and development expenses (5,388 ) (38,199 ) (43,587 ) (5,836 ) (56,503 ) (62,338 ) Selling, general and administrative expenses (11,774 ) (9,439 ) (21,213 ) (7,528 ) (10,691 ) (18,219 ) Other operating income and expenses (44 ) 131 86 7 482 489 Total operating expenses (26,426 ) (48,715 ) (75,142 ) (32,063 ) (67,905 ) (99,968 ) Operating income (loss) before tax (21,756 ) 3,102 (18,655 ) (13,818 ) (43,569 ) (57,387 ) Net financial gain (loss) (148 ) (487 ) (635 ) (584 ) 1,015 431 Net income (loss) (21,904 ) 2,615 (19,290 ) (14,402 ) (42,554 ) (56,956 ) Non controlling interests 7,069 — 7,069 5,169 — 5,169 Net income (loss) attributable to shareholders of Cellectis (14,835 ) 2,615 (12,221 ) (9,233 ) (42,554 ) (51,787 ) R&D non-cash 573 4,177 4,750 532 3,703 4,235 SG&A non-cash 1,879 1,667 3,546 (918 ) 916 (2 ) Adjustment of share-based compensation attributable to shareholders of Cellectis 2,452 5,844 8,296 (385 ) 4,619 4,233 Adjusted net income (loss) attributable to shareholders of Cellectis (12,383 ) 8,459 (3,924 ) (9,619 ) (37,935 ) (47,554 ) Depreciation and amortization (980 ) (3,212 ) (4,192 ) (1,218 ) (5,954 ) (7,173 ) Additions to tangible and intangible assets 355 29,832 30,187 308 11,020 11,327 Details of key performance indicators by reportable s e For the three-month period ended June 30, 2020 For the three-month period ended June 30, 2021 $ in thousands Plants Therapeutics Total reportable Plants Therapeutics Total reportable External revenues 2,293 607 2,900 11,728 (552 ) 11,176 External other income — 1,716 1,716 1,528 1,911 3,439 External revenues and other income 2,293 2,323 4,616 13,256 1,359 14,615 Cost of revenue (5,339 ) (487 ) (5,827 ) (11,337 ) (418 ) (11,754 ) Research and development expenses (2,754 ) (20,107 ) (22,862 ) (2,810 ) (28,336 ) (31,147 ) Selling, general and administrative expenses (5,311 ) (3,759 ) (9,070 ) (3,410 ) (5,933 ) (9,343 ) Other operating income and expenses (24 ) 135 111 31 118 150 Total operating expenses (13,429 ) (24,218 ) (37,647 ) (17,526 ) (34,569 ) (52,096 ) Operating income (loss) before tax (11,136 ) (21,895 ) (33,031 ) (4,270 ) (33,210 ) (37,481 ) Financial gain (loss) 185 (3,006 ) (2,821 ) (294 ) (3,836 ) (4,129 ) Net income (loss) (10,951 ) (24,901 ) (35,852 ) (4,564 ) (37,046 ) (41,610 ) Non controlling interests 3,589 — 3,589 1,691 — 1,691 Net income (loss) attributable to shareholders of Cellectis (7,362 ) (24,901 ) (32,263 ) (2,873 ) (37,046 ) (39,919 ) R&D non-cash stock-based expense attributable to shareholder of Cellectis (21 ) 1,749 1,728 271 2,398 2,669 SG&A non-cash stock-based expense attributable to shareholder of Cellectis 1,132 580 1,712 373 593 966 Adjustment of share-based compensation attributable to shareholders of Cellectis 1,112 2,329 3,441 644 2,991 3,635 Adjusted net income (loss) attributable to shareholders of Cellectis (6,250 ) (22,572 ) (28,823 ) (2,229 ) (34,055 ) (36,285 ) Depreciation and amortization (490 ) (1,657 ) (2,147 ) (614 ) (2,768 ) (3,382 ) Additions to tangible and intangible assets 207 16,003 16,210 39 4,688 4,727

Right-of-use assets (Tables)

Right-of-use assets (Tables)	6 Months Ended
	Jun. 30, 2021
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Disclosure Of Detailed Information About Breakdown Of Right Of Use Assets Explanatory	The breakdown of right-of-use Building Office and Total $ in thousands Net book value as of January 1, 2020 43,111 2,500 45,612 Additions to tangible assets 18,806 2,141 20,947 Depreciation expense (2,251 ) (647 ) (2,899 ) Translation adjustments (8 ) 16 9 Net book value as of June 30, 2020 59,659 4,010 63,669 Gross value at end of period 65,984 5,316 71,300 Accumulated depreciation and impairment at end of period (6,325 ) (1,306 ) (7,631 ) Net book value as of January 1, 2021 62,424 11,421 73,845 Additions (139 ) 5,666 5,527 Depreciation expense (2,882 ) (1,771 ) (4,653 ) Translation adjustments (584 ) (85 ) (668 ) Net book value as of June 30, 2021 58,819 15,232 74,050 Gross value at end of period 70,818 18,871 89,689 Accumulated depreciation at end of period (11,999 ) (3,639 ) (15,638 )

Property, plant and equipment (

Property, plant and equipment (Tables)	6 Months Ended
	Jun. 30, 2021
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Details of Property, Plant and Equipment	Lands and Technical Fixtures, Assets Total $ in thousands Net book value as of January 1, 2020 3,330 3,160 2,435 14,787 23,712 Additions to tangible assets 487 271 294 29,103 30,156 Disposal of tangible assets — (9 ) — (0 ) (9 ) Reclassification 674 164 186 (1,025 ) (1 ) Depreciation expense (166 ) (633 ) (415 ) — (1,214 ) Translation adjustments 8 0 (0 ) 0 8 Net book value as of June 30, 2020 4,332 2,955 2,500 42,866 52,653 Gross value at end of period 8,994 14,364 4,628 42,866 70,851 Accumulated depreciation and impairment at end of period (4,661 ) (11,409 ) (2,128 ) (0 ) (18,198 ) Net book value as of January 1, 2021 16,765 4,436 3,171 47,301 71,673 Additions to tangible assets 2,778 2,127 1,046 5,376 11,327 Disposal of tangible assets (40 ) (72 ) — (59 ) (171 ) Reclassification 1,105 4,568 (860 ) (4,859 ) (47 ) Depreciation expense (1,056 ) (1,399 ) (329 ) — (2,784 ) Translation adjustments (333 ) (83 ) (31 ) (73 ) (520 ) Net book value as of June 30, 2021 19,218 9,577 2,997 47,686 79,478 Gross value at end of period 25,844 24,821 4,603 47,686 102,954 Accumulated depreciation and impairment at end of period (6,626 ) (15,245 ) (1,606 ) (0 ) (23,476 )

Trade receivables and other c_2

Trade receivables and other current assets (Tables)	6 Months Ended
	Jun. 30, 2021
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Disclosure of Trade Receivables	8.1 Trade receivables As of December 31, As of June 30, $ in thousands Trade receivables 5,787 3,908 Valuation allowance (616 ) (31 ) Total net value of trade receivables 5,171 3,878
Disclosure of Subsidies Receivables	8.2 Subsidies receivables As of December 31, As of June 30, $ in thousands Research tax credit 10,703 5,654 Total subsidies receivables 10,703 5,654
Disclosure of Other Current Assets	8.3 Other current assets As of December 31, As of June 30, $ in thousands VAT receivables 3,093 2,147 Prepaid expenses and other prepayments 14,113 13,431 Tax and social receivables 227 270 Deferred expenses and other current assets 12,210 885 Total other current assets 29,643 16,733

Current financial assets and _2

Current financial assets and Cash and cash equivalents (Tables)	6 Months Ended
	Jun. 30, 2021
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Summary of Current Financial Assets and Cash and Cash Equivalents	As of December 31, 2020 Carrying Unrealized Estimated fair $ in thousands Current financial assets 27,091 — 27,091 Cash and cash equivalents 241,148 — 241,148 Current financial assets and cash and cash equivalents 268,239 — 268,239 As of June 30, 2021 Carrying Unrealized Estimated fair $ in thousands Current financial assets 3,393 — 3,393 Cash and cash equivalents 248,226 — 248,226 Current financial assets and cash and cash equivalents 251,619 — 251,619
Details of Cash and Cash Equivalents	As of December 31, As of June 30, $ in thousands Cash and bank accounts 164,586 192,661 Money market funds 13,977 13,971 Fixed bank deposits 62,585 41,594 Total cash and cash equivalents 241,148 248,226

Financial liabilities (Tables)

Financial liabilities (Tables)	6 Months Ended
	Jun. 30, 2021
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Detail of financial liabilities	10.1 Detail of financial liabilities As of December 31, As of June 30, $ in thousands Lease debts 75,764 75,763 State Guaranteed loan « PGE » 22,701 22,137 PPP loan 1,518 — Other non-current 4,617 1,339 Total non-current non-current 104,600 99,238 Lease debts 6,696 7,691 Total current financial liabilities 6,696 7,691 Trade payables 24,609 28,254 Other current liabilities 19,127 13,681 Total Financial liabilities 155,032 148,864
Due dates of the financial liabilities	10.2 Due dates of the financial liabilities Balance as of June 30, 2021 Book value Less than One One to Five More than $ in thousands Lease debts 83,454 7,691 34,026 41,736 Other financial liabilities 23,475 134 22,348 993 Financial liabilities 106,929 7,825 56,374 42,730 Trade payables 28,254 28,254 — — Other current liabilities 13,681 13,681 — — Total financial liabilities 148,864 49,760 56,374 42,730

Other current liabilities (Tabl

Other current liabilities (Tables)	6 Months Ended
	Jun. 30, 2021
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Summary of Other Current Liabilities	As of December 31, As of June 30, $ in thousands VAT Payables 81 201 Accruals for personnel related expenses 12,969 9,565 Other 6,077 3,915 Total 19,127 13,681

Deferred revenues and contrac_2

Deferred revenues and contract liabilities (Tables)	6 Months Ended
	Jun. 30, 2021
Text block1 [abstract]
Details of Deferred Revenues and Contract Liabilities	As of December 31, 2020 As of June 30, 2021 $ in thousands Deferred revenues and contract liabilities 452 423 Others — — Total Deferred revenue and contract liabilities 452 423

Share capital and premium rel_2

Share capital and premium related to the share capitals (Tables)	6 Months Ended
	Jun. 30, 2021
Text block1 [abstract]
Schedule of Classes of Share Capital	Nature of the Transactions Share Share Number of Nominal $ in thousands (except number of shares) in $ Balance as of January 1, 2020 2,767 843,478 42,465,669 0.05 Capital Increase 1 — 20,464 — Non-cash — 5,844 — — Other movements — — — — Balance as of June 30, 2020 2,768 849,322 42,486,133 0.05 Balance as of January 1, 2021 2,785 863,911 42,780,186 0.05 Capital increase (ATM) 146 47,688 2,415,630 — Exercise of share warrants, employee warrants and stock options 16 5,702 265,494 — Non-cash — 4,233 — — Transaction costs — (910 ) — — Other movements — (34 ) — — Balance as of June 30, 2021 2,947 920,591 45,461,310 0.05

Non-cash share-based compensa_2

Non-cash share-based compensation (Tables)	6 Months Ended
	Jun. 30, 2021
Statement [Line Items]
Summary of Number of Shares Outstanding and Weighted Average Grant Date Fair Value	Information on free shares activity follows: Number of Free shares Weighted-Average Grant Unvested balance at December 31, 2019 67,000 13.98 € Granted (1) 591,685 20.10 € Vested (3,000 ) 23.84 € Cancelled (26,035 ) 16.45 € Unvested balance at December 31, 2020 629,650 19.59 € Granted 332,041 12.78 € Vested (9,000 ) 17.45 € Cancelled (90,640 ) 16.32 € Unvested balance at June 30, 2021 862,051 17.33 € (1) 423,285 free shares have been granted in October 2020 under the Amended Second Free Shares 2018 Plan and are under non-market three 330,041 three 103,000 non-market
Warrants [member]
Statement [Line Items]
Summary of Information on Warrant Activity	Information on warrants activity follows: Warrants Weighted- Warrants Weighted- Remaining Balance as of December 31, 2019 852,260 35.35 € 918,927 35.12 € 6.9y Granted — — — — Exercised — — (19,702 ) 8.28 € Forfeited or Expired — — — — Balance as of December 31, 2020 899,225 27.15 € 899,225 27.15 € 5.3y Granted — — — — Exercised — — (3,000 ) 18.68 € Forfeited or Expired — — — — Balance as of June 30, 2021 896,225 27.18 € 896,225 27.18 € 4.9y
Stock options [member]
Statement [Line Items]
Summary of assumptions Vesting Details	The weighted-average fair values of stock options granted and the assumptions used for the Black-Scholes option pricing model were as follows: 2020 2021 Weighted-Average fair values of stock options granted 7.00€ 5.76€ Assumptions: Risk-free interest rate 0.00% 0.00% Share entitlement per options 1 1 Exercise price 8.27€ - 15.84€ 14.36€ - 19.44€ Grant date share fair value 9.14€ - 15.76€ 12.69€ - 16.54€ Expected volatility 61.3% - 62.8% 59.9% - 60.1% Expected term (in years) 6.15 6.15 Vesting conditions Service Service Vesting period Graded Graded
Summary of Information on Stock Option Activity	Information on stock option activity follows: Options Weighted- Options Weighted- Remaining Balance as of December 31, 2019 6,922,172 26.30 € 9,672,382 24.22 € 6.8y Granted — — 479,000 12.54 € Exercised — — (291,053 ) 17.86 € Forfeited or Expired — — (373,672 ) 20.61 € Balance as of December 31, 2020 8,002,398 25.28 € 9,486,657 23.97 € 5.9y Granted — — 955,485 19.32 Exercised — — (253,494 ) 18.49 € Forfeited or Expired — — (535,638 ) 19.81 € Balance as of June, 2021 7,750,761 25.34 € 9,653,010 23.88 € 5.8y
Stock options [member] | Calyxt Inc. [member]
Statement [Line Items]
Summary of assumptions Vesting Details	The estimated fair values of stock options granted and the assumptions used for the Black-Scholes option pricing model were as follows: 2020 2021 Weighted-Average fair values of stock options granted $5.19 $4.54 Assumptions: Risk-free interest rate 1.7% 0.6% - 1.1% Share entitlement per options 1 1 Expected volatility 77.4% 80.1% - 82.0% Expected term (in years) 6.9 5.5 - 6.5 Vesting conditions Service Service Vesting period Graded Graded
Summary of Information on Stock Option Activity	Information on stock option activity follows: Options Weighted- Options Weighted- Remaining Balance as of December 31, 2019 1,789,567 $ 8.73 4,481,359 $ 11.73 6.8y Granted 887,765 $ 4.67 Exercised (58,575 ) $ 3.60 Forfeited or Expired (689,376 ) $ 12.89 Balance as of December 31, 2020 2,347,663 $ 10.15 4,621,173 $ 10.30 6.2y Granted 456,959 $ 5.71 Exercised (61,372 ) $ 3.70 Forfeited or Expired (550,110 ) $ 10.57 Balance as of June 30, 2021 2,412,501 $ 10.49 4,466,650 $ 9.89 5.8y
Restricted Stock Unit [Member] | Calyxt Inc. [member]
Statement [Line Items]
Summary of Information on Restricted Stock Unit Activity	Information on restricted stock unit activity follows: Number of Restricted Weighted-Average Unvested balance at December 31, 2020 547,807 $ 9.49 Granted 234,504 $ 5.61 Vested (69,323 ) $ 9.25 Cancelled (133,348 ) $ 12.49 Unvested balance at June 30, 2021 579,640 $ 7.26
Performance Stock Unit [Member] | Calyxt Inc. [member]
Statement [Line Items]
Summary of assumptions Detail Of Stock Unit Activity Performance Stock	The fair value of the performance stock units and the assumptions used for the Monte Carlo simulation were as follows: Date of grant 06/28/2019 Estimated fair values of performance stock units granted $ 7.06 Assumptions: Risk-free interest rate 1.71 % Expected volatility 75.0 % Expected term (in years) 3.0 years
Summary of Information on Performance Stock Unit Activity	Information on performance stock unit activity follows: Number of Weighted- Unvested balance at December 31, 2020 311,667 $ 7.06 Granted — — Vested — — Cancelled (166,667 ) Unvested balance at June 30, 2021 145,000 $ 7.06

Earnings per share (Tables)

Earnings per share (Tables)	6 Months Ended
	Jun. 30, 2021
Text block1 [abstract]
Earnings per share	For the six-month period ended June 30, 2020 2021 Net income (loss) attributable to shareholders of Cellectis ($ in thousands) (12,221 ) (51,787 ) Adjusted weighted average number of outstanding shares, used to calculate both basic and diluted net result per share 42,469,080 44,163,914 Basic / Diluted net income (loss) per share attributable to shareholders of Cellectis Basic net income (loss) attributable to shareholders of Cellectis per share ( $ /share) (0.29 ) (1.17 ) Diluted net income (loss) attributable to shareholders of Cellectis per share ( $ /share) (0.29 ) (1.17 ) For the three-month period ended 2020 2021 Net income (loss) attributable to shareholders of Cellectis ($ in thousands) (32,263 ) (39,919 ) Adjusted weighted average number of outstanding shares, used to calculate both basic and diluted net result per share 42,472,490 45,461,310 Basic / Diluted net income (loss) per share attributable to shareholders of Cellectis per share ($ / share) Basic net income (loss) per share ($ /share) (0.76 ) (0.88 ) Diluted net income (loss) per share ($ /share) (0.76 ) (0.88 )

Provisions (Tables)

Provisions (Tables)	6 Months Ended
	Jun. 30, 2021
Text block1 [abstract]
Details of Provisions	31/12/2020 Additions Amounts Reversals OCI 30/06/2021 $ in thousands Pension 4,010 299 — — (699 ) 3,610 Loss on contract — — — — — — Employee litigation and severance 560 30 (101 ) (84 ) (15 ) 391 Commercial litigation 571 901 (194 ) (246 ) (25 ) 1,006 Total 5,141 1,230 (296 ) (330 ) (739 ) 5,007

Commitments (Tables)

Commitments (Tables)	6 Months Ended
	Jun. 30, 2021
Text block1 [abstract]
Details of commitments	As of June 30, 2021 Total Less than 1 1 - 3 3 - 5 More than 5 $ in thousands License agreements 18,345 1,530 3,060 3,060 10,695 Manufacturing agreements 947 930 18 — — Clinical & R&D agreements 288 234 54 — — Construction agreements 1,687 1,687 — — — IT licensing agreements 1,335 445 890 — — Other agreements 6,839 6,839 — — — Total commitments 29,442 11,665 4,022 3,060 10,695

The Company - Additional Inform

The Company - Additional Information (Detail)	6 Months Ended
	Jun. 30, 2021
Calyxt Inc [member]
Disclosure of subsidiaries [line items]
Ownership interest in subsidiary	64.40%

Accounting Principles - Additio

Accounting Principles - Additional Information (Detail)	6 Months Ended	12 Months Ended
	Jun. 30, 2021	Dec. 31, 2020
Cellectis, Inc. [member]
Disclosure of changes in accounting estimates [line items]
Ownership interest in subsidiary	100.00%
Calyxt Inc [member]
Disclosure of changes in accounting estimates [line items]
Ownership interest in subsidiary	64.40%
Non-controlling shareholders interest	35.60%	35.30%
Cellectis Biologics [member]
Disclosure of changes in accounting estimates [line items]
Ownership interest in subsidiary	100.00%

Information Concerning the Gr_3

Information Concerning the Group's Consolidated Operations - Revenues by Country of Origin and Other Income (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Disclosure of revenue [line items]
Revenues	$ 11,176	$ 2,900	$ 36,777	$ 52,993
Research tax credit	1,909	1,725	4,272	3,573
Subsidies and other	1,530	(10)	1,532	(79)
Other income	3,439	1,716	5,804	3,494
Total revenues and other income	14,615	4,616	42,581	56,487
France [member]
Disclosure of revenue [line items]
Revenues	(552)	607	20,061	48,323
United States [member]
Disclosure of revenue [line items]
Revenues	$ 11,728	$ 2,293	$ 16,716	$ 4,670

Information Concerning the Gr_4

Information Concerning the Group's Consolidated Operations - Revenues by Nature (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Disclosure of revenue [line items]
Recognition of previously deferred upfront payments				$ 19,535
Other revenues	$ (551)	$ 110	$ 20,014	27,536
Collaboration agreements	(551)	110	20,014	47,071
Licenses	(48)	466		1,233
Products & services	11,775	2,324	16,763	4,689
Total revenues	$ 11,176	$ 2,900	$ 36,777	$ 52,993

Information Concerning the Gr_5

Information Concerning the Group's Consolidated Operations - Additional Information (Detail) $ in Millions	6 Months Ended
	Jun. 30, 2021USD ($)
Consolidated operations [line items]
Upfront amount	$ 15
ALLO715 [Member]
Consolidated operations [line items]
Milestone Revenue	5.1
Calyxt Inc [member] | High Oleic Soyabean Meal [Member]
Consolidated operations [line items]
Revenue from sale of food	$ 16.7

Information Concerning the Gr_6

Information Concerning the Group's Consolidated Operations - Details of Operating Expenses by Nature (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Expense by nature [line Items]
Cost of good sold	$ (11,375)	$ (5,320)	$ (18,706)	$ (9,204)
Royalty expenses	(380)	(507)	(1,194)	(1,223)
Cost of revenue	(11,754)	(5,827)	(19,899)	(10,428)
Total research and development expenses	(31,147)	(22,862)	(62,338)	(43,587)
Total selling, general and administrative expenses	(9,343)	(9,070)	(18,219)	(21,213)
Research and Development Expenses [member]
Expense by nature [line Items]
Wages and salaries	(9,986)	(6,790)	(20,863)	(13,276)
Social charges on free shares and stock option grants	(84)		(845)
Non-cash stock based compensation expense	(2,819)	(2,410)	(4,530)	(5,014)
Personnel expenses	(12,888)	(9,200)	(26,237)	(18,290)
Purchases and external expenses	(15,845)	(11,775)	(30,897)	(21,743)
Other	(2,413)	(1,887)	(5,204)	(3,555)
Total research and development expenses	(31,147)	(22,862)	(62,338)	(43,587)
Personnel Expenses [member]
Expense by nature [line Items]
Wages and salaries	(13,192)	(9,895)	(30,046)	(21,165)
Social charges on free shares and stock option grants	(100)		(1,195)
Non-cash stock based compensation expense	(3,990)	(4,651)	(4,020)	(9,427)
Personnel expenses	(17,283)	(14,546)	(35,261)	(30,592)
Selling, General and Administrative Expenses [member]
Expense by nature [line Items]
Wages and salaries	(3,206)	(3,105)	(9,183)	(7,890)
Social charges on free shares and stock option grants	(17)		(350)
Non-cash stock based compensation expense	(1,172)	(2,240)	509	(4,413)
Personnel expenses	(4,395)	(5,345)	(9,024)	(12,302)
Purchases and external expenses	(3,600)	(2,653)	(6,419)	(6,980)
Other	(1,348)	(1,072)	(2,776)	(1,931)
Total selling, general and administrative expenses	$ (9,343)	$ (9,070)	$ (18,219)	$ (21,213)

Information Concerning the Gr_7

Information Concerning the Group's Consolidated Operations - Summary of Key Performance Indicators by Reportable Segments (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Disclosure of operating segments [line items]
External revenues	$ 11,176	$ 2,900	$ 36,777	$ 52,993
External revenues and other income	14,615	4,616	42,581	56,487
Cost of revenue	(11,754)	(5,827)	(19,899)	(10,428)
Research and development expenses	(31,147)	(22,862)	(62,338)	(43,587)
Selling, general and administrative expenses	(9,343)	(9,070)	(18,219)	(21,213)
Other operating income and expenses	150	111	489	86
Total operating expenses	(52,096)	(37,647)	(99,968)	(75,142)
Operating income (loss) before tax	(37,481)	(33,031)	(57,387)	(18,655)
Financial gain (loss)	(4,129)	(2,821)	431	(635)
Net income (loss) from discontinued operations	(41,610)	(35,852)	(56,956)	(19,290)
Non controlling interests	1,691	3,589	5,169	7,069
Net income (loss) attributable to shareholders of Cellectis	(39,919)	(32,263)	(51,787)	(12,221)
Adjustment of share-based compensation attributable to shareholders of Cellectis	3,635	3,441	4,233	8,296
Adjusted net income (loss) attributable to shareholders of Cellectis	(36,285)	(28,823)	(47,554)	(3,924)
Depreciation and amortization	(3,382)	(2,147)	(7,173)	(4,192)
Additions to tangible and intangible assets	4,727	16,210	11,327	30,187
Research and Development [member]
Disclosure of operating segments [line items]
Adjustment of share-based compensation attributable to shareholders of Cellectis	2,669	1,728	4,235	4,750
Selling, General and Administration [member]
Disclosure of operating segments [line items]
Adjustment of share-based compensation attributable to shareholders of Cellectis	966	1,712	(2)	3,546
Plants [member]
Disclosure of operating segments [line items]
External revenues and other income	13,256	2,293	18,244	4,670
Cost of revenue	(11,337)	(5,339)	(18,706)	(9,219)
Research and development expenses	(2,810)	(2,754)	(5,836)	(5,388)
Selling, general and administrative expenses	(3,410)	(5,311)	(7,528)	(11,774)
Other operating income and expenses	31	(24)	7	(44)
Total operating expenses	(17,526)	(13,429)	(32,063)	(26,426)
Operating income (loss) before tax	(4,270)	(11,136)	(13,818)	(21,756)
Financial gain (loss)	(294)	185	(584)	(148)
Net income (loss) from discontinued operations	(4,564)	(10,951)	(14,402)	(21,904)
Non controlling interests	1,691	3,589	5,169	7,069
Net income (loss) attributable to shareholders of Cellectis	(2,873)	(7,362)	(9,233)	(14,835)
Adjustment of share-based compensation attributable to shareholders of Cellectis	644	1,112	(385)	2,452
Adjusted net income (loss) attributable to shareholders of Cellectis	(2,229)	(6,250)	(9,619)	(12,383)
Depreciation and amortization	(614)	(490)	(1,218)	(980)
Additions to tangible and intangible assets	39	207	308	355
Plants [member] | Research and Development [member]
Disclosure of operating segments [line items]
Adjustment of share-based compensation attributable to shareholders of Cellectis	271	(21)	532	573
Plants [member] | Selling, General and Administration [member]
Disclosure of operating segments [line items]
Adjustment of share-based compensation attributable to shareholders of Cellectis	373	1,132	(918)	1,879
Therapeutics [member]
Disclosure of operating segments [line items]
External revenues and other income	1,359	2,323	24,337	51,817
Cost of revenue	(418)	(487)	(1,194)	(1,207)
Research and development expenses	(28,336)	(20,107)	(56,503)	(38,199)
Selling, general and administrative expenses	(5,933)	(3,759)	(10,691)	(9,439)
Other operating income and expenses	118	135	482	131
Total operating expenses	(34,569)	(24,218)	(67,905)	(48,715)
Operating income (loss) before tax	(33,210)	(21,895)	(43,569)	3,102
Financial gain (loss)	(3,836)	(3,006)	1,015	(487)
Net income (loss) from discontinued operations	(37,046)	(24,901)	(42,554)	2,615
Net income (loss) attributable to shareholders of Cellectis	(37,046)	(24,901)	(42,554)	2,615
Adjustment of share-based compensation attributable to shareholders of Cellectis	2,991	2,329	4,619	5,844
Adjusted net income (loss) attributable to shareholders of Cellectis	(34,055)	(22,572)	(37,935)	8,459
Depreciation and amortization	(2,768)	(1,657)	(5,954)	(3,212)
Additions to tangible and intangible assets	4,688	16,003	11,020	29,832
Therapeutics [member] | Research and Development [member]
Disclosure of operating segments [line items]
Adjustment of share-based compensation attributable to shareholders of Cellectis	2,398	1,749	3,703	4,177
Therapeutics [member] | Selling, General and Administration [member]
Disclosure of operating segments [line items]
Adjustment of share-based compensation attributable to shareholders of Cellectis	593	580	916	1,667
Operating Segments [member]
Disclosure of operating segments [line items]
External revenues	11,176	2,900	36,777	52,993
Operating Segments [member] | Plants [member]
Disclosure of operating segments [line items]
External revenues	11,728	2,293	16,716	4,670
Operating Segments [member] | Therapeutics [member]
Disclosure of operating segments [line items]
External revenues	(552)	607	20,061	48,323
Inter-segment Revenues [member]
Disclosure of operating segments [line items]
External other income	3,439	1,716	5,804	3,494
Inter-segment Revenues [member] | Plants [member]
Disclosure of operating segments [line items]
External other income	1,528		1,528
Inter-segment Revenues [member] | Therapeutics [member]
Disclosure of operating segments [line items]
External other income	$ 1,911	$ 1,716	$ 4,276	$ 3,494

Impairment Tests - Additional I

Impairment Tests - Additional Information (Detail) - USD ($)	3 Months Ended	6 Months Ended
	Jun. 30, 2021	Jun. 30, 2021
Disclosure of impairment loss and reversal of impairment loss [line items]
Impairment of assets	$ 0	$ 0

Right-of-use Assets - Details I

Right-of-use Assets - Details Information About Breakdown Of Right Of Use Assets (Detail) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020
Disclosure of quantitative information about right-of-use assets [line items]
Beginning balance	$ 73,845
Ending balance	74,050
Right-of-use assets [member]
Disclosure of quantitative information about right-of-use assets [line items]
Beginning balance	73,845	$ 45,612
Additions to tangible assets	5,527	20,947
Depreciation expense	(4,653)	(2,899)
Translation adjustments	(668)	9
Ending balance	74,050	63,669
Gross value at end of period	89,689	71,300
Accumulated depreciation and impairment at end of period	(15,638)	(7,631)
Building lease [member] | Right-of-use assets [member]
Disclosure of quantitative information about right-of-use assets [line items]
Beginning balance	62,424	43,111
Additions to tangible assets	(139)	18,806
Depreciation expense	(2,882)	(2,251)
Translation adjustments	(584)	(8)
Ending balance	58,819	59,659
Gross value at end of period	70,818	65,984
Accumulated depreciation and impairment at end of period	(11,999)	(6,325)
Office and laboratory equipment [member] | Right-of-use assets [member]
Disclosure of quantitative information about right-of-use assets [line items]
Beginning balance	11,421	2,500
Additions to tangible assets	5,666	2,141
Depreciation expense	(1,771)	(647)
Translation adjustments	(85)	16
Ending balance	15,232	4,010
Gross value at end of period	18,871	5,316
Accumulated depreciation and impairment at end of period	$ (3,639)	$ (1,306)

Property, Plant and Equipment -

Property, Plant and Equipment - Disclosure of Property, Plant and Equipment (Detail) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020
Disclosure of detailed information about property, plant and equipment [line items]
Beginning balance	$ 71,673	$ 23,712
Additions to tangible assets	11,327	30,156
Disposal of tangible assets	(171)	(9)
Reclassification	(47)	(1)
Depreciation expense	(2,784)	(1,214)
Translation adjustments	(520)	8
Ending balance	79,478	52,653
Gross value at end of period	102,954	70,851
Accumulated depreciation and impairment at end of period	(23,476)	(18,198)
Land and Buildings [member]
Disclosure of detailed information about property, plant and equipment [line items]
Beginning balance	16,765	3,330
Additions to tangible assets	2,778	487
Disposal of tangible assets	(40)
Reclassification	1,105	674
Depreciation expense	(1,056)	(166)
Translation adjustments	(333)	8
Ending balance	19,218	4,332
Gross value at end of period	25,844	8,994
Accumulated depreciation and impairment at end of period	(6,626)	(4,661)
Technical Equipment [member]
Disclosure of detailed information about property, plant and equipment [line items]
Beginning balance	4,436	3,160
Additions to tangible assets	2,127	271
Disposal of tangible assets	(72)	(9)
Reclassification	4,568	164
Depreciation expense	(1,399)	(633)
Translation adjustments	(83)	0
Ending balance	9,577	2,955
Gross value at end of period	24,821	14,364
Accumulated depreciation and impairment at end of period	(15,245)	(11,409)
Fixtures, Fittings and Other Equipment [member]
Disclosure of detailed information about property, plant and equipment [line items]
Beginning balance	3,171	2,435
Additions to tangible assets	1,046	294
Reclassification	(860)	186
Depreciation expense	(329)	(415)
Translation adjustments	(31)	0
Ending balance	2,997	2,500
Gross value at end of period	4,603	4,628
Accumulated depreciation and impairment at end of period	(1,606)	(2,128)
Assets Under Construction [member]
Disclosure of detailed information about property, plant and equipment [line items]
Beginning balance	47,301	14,787
Additions to tangible assets	5,376	29,103
Disposal of tangible assets	(59)	0
Reclassification	(4,859)	(1,025)
Translation adjustments	(73)	0
Ending balance	47,686	42,866
Gross value at end of period	47,686	42,866
Accumulated depreciation and impairment at end of period	$ 0	$ 0

Property, Plant and Equipment_2

Property, Plant and Equipment - Additional Information (Detail) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020
Disclosure of detailed information about property, plant and equipment [line items]
Assets under construction	$ 11,327	$ 30,156
Other Equipment [Member]
Disclosure of detailed information about property, plant and equipment [line items]
Addition to tangible assets	1,100
Technical Equipments [Member]
Disclosure of detailed information about property, plant and equipment [line items]
Addition to tangible assets	2,100
Assets Under Construction [Member] | Paris [member]
Disclosure of detailed information about property, plant and equipment [line items]
Assets under construction	2,000
Assets Under Construction [Member] | North Carolina [Member]
Disclosure of detailed information about property, plant and equipment [line items]
Assets under construction	41,400
Calyxt Inc and Cellectis Sites [member]
Disclosure of detailed information about property, plant and equipment [line items]
Addition to tangible assets	2,800
Calyxt Inc and Cellectis Sites [member] | Other Equipment [Member]
Disclosure of detailed information about property, plant and equipment [line items]
Addition to tangible assets	3,200
Cellectis [member] | Assets Put In Service [member] | Raleigh And Paris [Member]
Disclosure of detailed information about property, plant and equipment [line items]
Assets put in service	$ 3,800

Non-current Financial Assets -

Non-current Financial Assets - Additional Information (Detail) - USD ($) $ in Millions	Jun. 30, 2021	Feb. 12, 2021
Cytovia Therapeutics, Inc. [member]
Categories of non-current financial assets [Line Items]
Non-current financial assets		$ 15
Raleigh's building [member]
Categories of non-current financial assets [Line Items]
Non-current financial assets	$ 2.6
Stonebriar's equipment [member]
Categories of non-current financial assets [Line Items]
Non-current financial assets	$ 1.9

Trade Receivables and Other C_3

Trade Receivables and Other Current Assets - Disclosure of Trade Receivables (Detail) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Trade and other receivables [abstract]
Trade receivables	$ 3,908	$ 5,787
Valuation allowance	(31)	(616)
Total net value of trade receivables	$ 3,878	$ 5,171

Trade Receivables and Other C_4

Trade Receivables and Other Current Assets - Disclosure of Subsidies Receivables (Detail) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Receivables1 [abstract]
Research tax credit	$ 5,654	$ 10,703
Total subsidies receivables	$ 5,654	$ 10,703

Trade Receivables and Other C_5

Trade Receivables and Other Current Assets - Additional Information (Detail) - USD ($) $ in Millions	Jun. 30, 2021	Dec. 31, 2020
Subsidies receivables and other current assets [line items]
Deferred expenses and other current assets payments to suppliers		$ 2.7
Deferred expenses and other current assets right to obtain equipment		3
Cellectis [member]
Subsidies receivables and other current assets [line items]
Deferred expenses and other current assets employee stock option receivables		$ 6.2
France [member]
Subsidies receivables and other current assets [line items]
Research tax credit receivables	$ 4.2
France [member] | Previously stated [member]
Subsidies receivables and other current assets [line items]
Research tax credit receivables	$ 1.3

Trade Receivables and Other C_6

Trade Receivables and Other Current Assets - Disclosure of Other Current Assets (Detail) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Other Current Assets [abstract]
VAT receivables	$ 2,147	$ 3,093
Prepaid expenses and other prepayments	13,431	14,113
Tax and social receivables	270	227
Deferred expenses and other current assets	885	12,210
Total other current assets	$ 16,733	$ 29,643

Current Financial Assets and _3

Current Financial Assets and Cash and Cash Equivalents - Summary of Current Financial Assets and Cash and Cash Equivalents (Detail) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020	Jun. 30, 2020	Dec. 31, 2019
Disclosure of current financial assets and cash and cash equivalents [line items]
Current financial assets	$ 3,393	$ 27,091
Cash and cash equivalents	248,226	241,148	$ 260,711	$ 340,522
Carrying Value [member]
Disclosure of current financial assets and cash and cash equivalents [line items]
Current financial assets	3,393	27,091
Cash and cash equivalents	248,226	241,148
Current financial assets and cash and cash equivalents	251,619	268,239
Estimated Fair Value [member]
Disclosure of current financial assets and cash and cash equivalents [line items]
Current financial assets	3,393	27,091
Cash and cash equivalents	248,226	241,148
Current financial assets and cash and cash equivalents	$ 251,619	$ 268,239

Current Financial Assets and _4

Current Financial Assets and Cash and Cash Equivalents - Additional Information (Detail) - USD ($) $ in Millions	Jun. 30, 2021	Dec. 31, 2020
Trading securities [member]
Disclosure of current financial assets and cash and cash equivalents [line items]
Nominal value amount	$ 0	$ 11.7
Fair value amount	0	$ 11.7
Calyxt [member]
Disclosure of current financial assets and cash and cash equivalents [line items]
Restricted cash	1
Short term restricted cash	0.4
Manufacturing Facility [Member]
Disclosure of current financial assets and cash and cash equivalents [line items]
Short term restricted cash	$ 3

Current Financial Assets and _5

Current Financial Assets and Cash and Cash Equivalents - Summary of Cash and Cash Equivalents (Detail) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020	Jun. 30, 2020	Dec. 31, 2019
Cash and cash equivalents [abstract]
Cash and bank accounts	$ 192,661	$ 164,586
Money market funds	13,971	13,977
Fixed bank deposits	41,594	62,585
Total cash and cash equivalents	$ 248,226	$ 241,148	$ 260,711	$ 340,522

Financial Liabilities - Schedul

Financial Liabilities - Schedule of Financial Liabilities (Detail) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Categories of financial liabilities [abstract]
Lease debts	$ 75,763	$ 75,764
State Guaranteed loan « PGE »	22,137	22,701
PPP loan		1,518
Other non-current financial liabilities	1,339	4,617
Total non-current financial liabilities and non-current lease debts	99,238	104,600
Lease debts	7,691	6,696
Total current financial liabilities	7,691	6,696
Trade payables	28,254	24,609
Other current liabilities	13,681	19,127
Total Financial liabilities	$ 148,864	$ 155,032

Financial Liabilities - Sched_2

Financial Liabilities - Schedule Representing Due Dates of the Financial Liabilities (Detail) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Disclosure of offsetting of financial liabilities [line items]
Lease debts	$ 83,454
Other financial liabilities	23,475
Financial liabilities	106,929
Trade payables	28,254	$ 24,609
Other current liabilities	13,681	19,127
Total Financial liabilities	148,864	$ 155,032
Less than One Year [member]
Disclosure of offsetting of financial liabilities [line items]
Lease debts	7,691
Other financial liabilities	134
Financial liabilities	7,825
Trade payables	28,254
Other current liabilities	13,681
Total Financial liabilities	49,760
One to Five Years [member]
Disclosure of offsetting of financial liabilities [line items]
Lease debts	34,026
Other financial liabilities	22,348
Financial liabilities	56,374
Total Financial liabilities	56,374
More than Five Years [member]
Disclosure of offsetting of financial liabilities [line items]
Lease debts	41,736
Other financial liabilities	993
Financial liabilities	42,730
Total Financial liabilities	$ 42,730

Financial liabilities - Additio

Financial liabilities - Additional Information (Detail) $ in Thousands, € in Millions	6 Months Ended
	Jun. 30, 2021USD ($)	Jun. 30, 2021EUR (€)	Dec. 31, 2020USD ($)
Disclosure of offsetting of financial liabilities [line items]
Secured Borrowings	$ 22,137		$ 22,701
New York [Member]
Disclosure of offsetting of financial liabilities [line items]
Borrowings	1,300
Paycheck Protection Program Loan [Member]
Disclosure of offsetting of financial liabilities [line items]
Borrowings			$ 1,500
State Guaranteed Loan [Member] | Major Borrowing Transactions [Member]
Disclosure of offsetting of financial liabilities [line items]
Secured Borrowings	$ 22,000	€ 18.5
Guaranteed borrowing amount, percentage	90.00%
State Guaranteed Loan [Member] | Major Borrowing Transactions [Member] | Bottom of range [member]
Disclosure of offsetting of financial liabilities [line items]
Fixed interest rate	0.31%	0.31%
State Guaranteed Loan [Member] | Major Borrowing Transactions [Member] | Top of range [member]
Disclosure of offsetting of financial liabilities [line items]
Fixed interest rate	3.35%	3.35%

Other Current Liabilities - Sum

Other Current Liabilities - Summary of Other Current Liabilities (Detail) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Miscellaneous current liabilities [abstract]
VAT Payables	$ 201	$ 81
Accruals for personnel related expenses	9,565	12,969
Other	3,915	6,077
Total	$ 13,681	$ 19,127

Deferred Revenues and Contrac_3

Deferred Revenues and Contract Liabilities - Summary of Deferred Revenues and Contract Liabilities (Detail) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Accruals and deferred income [abstract]
Deferred revenues and contract liabilities	$ 423	$ 452
Others
Total Deferred revenue and contract liabilities	$ 423	$ 452

Share Capital and Premium Rel_3

Share Capital and Premium Related to The Share Capitals - Schedule of Classes of Share Capital (Detail) - USD ($) $ / shares in Units, $ in Thousands	6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020
Disclosure of classes of share capital [line items]
Balance at beginning of year	42,780,186	42,465,669
Capital increase by issuance of common shares	2,415,630	20,464
Exercise of share warrants, employee warrants and stock options	265,494
Balance at end of year	45,461,310	42,486,133
Nominal value	$ 0.05	$ 0.05
Premiums Related to Share Capital [member]
Disclosure of classes of share capital [line items]
Beginning balance	$ 863,911	$ 843,478
Capital Increase (ATM)	47,688
Exercise of share warrants, employee warrants and stock options	5,702
Non-cash stock based compensation expense	4,233	5,844
Transaction costs	(910)
Other movements	(34)
Balance at end of year	920,591	849,322
Share Capital Ordinary Shares [member]
Disclosure of classes of share capital [line items]
Beginning balance	2,785	2,767
Capital Increase (ATM)	146	1
Exercise of share warrants, employee warrants and stock options	16
Balance at end of year	$ 2,947	$ 2,768

Share Capital and Premium Rel_4

Share Capital and Premium Related to The Share Capitals - Additional Information (Detail) $ in Thousands	6 Months Ended
	Jun. 30, 2021USD ($)shares
Capital structure [line items]
Transaction costs | $	$ 910	[1]
ATM financing program [member]
Capital structure [line items]
Number of shares issued | shares	2,415,630
Exercise of share warrants, employee warrants and stock options | shares	265,494
Transaction costs | $	$ 900
[1]	These costs correspond to the issuance costs related to the At-The-Market (“ATM”) financing program were recorded as a reduction of share premium, in anticipation of share issuances that occurred in April 2021

Non-cash share-based compensa_3

Non-cash share-based compensation - Additional Information (Detail) $ in Millions	6 Months Ended
	Jun. 30, 2021USD ($)Agreement	Jun. 30, 2020USD ($)
Disclosure of terms and conditions of share-based payment arrangement [line items]
Expected dividend yield	0.00%
Vesting period, years	4 years
Stock option expire, years	10 years
Calyxt Inc. [member] | Restricted Period [Member]
Disclosure of terms and conditions of share-based payment arrangement [line items]
Vesting description	Restricted stock units generally vest and become unrestricted over five years after the date of grant.
Performance Stock Unit [Member] | Calyxt Inc. [member]
Disclosure of terms and conditions of share-based payment arrangement [line items]
Share based arrangement number of other equity instruments granted | Agreement	311,667
Share based payment expense		$ 0.2
Gain on forfeiture of shares	$ 0.3
Performance Stock Unit [Member] | Calyxt Inc. [member] | Bottom of range [member]
Disclosure of terms and conditions of share-based payment arrangement [line items]
Share Based Payment Arrangement Percentage Payout	0.00%
Performance Stock Unit [Member] | Calyxt Inc. [member] | Top of range [member]
Disclosure of terms and conditions of share-based payment arrangement [line items]
Share Based Payment Arrangement Percentage Payout	120.00%
Performance Stock Unit [Member] | Calyxt Inc. [member] | Performance Period [Member]
Disclosure of terms and conditions of share-based payment arrangement [line items]
Share Based Arrangement Service Period	3 years
Performance Stock Unit [Member] | Calyxt Inc. [member] | Restricted Period [Member]
Disclosure of terms and conditions of share-based payment arrangement [line items]
Share Based Arrangement Service Period	2 years
Stock options [member]
Disclosure of terms and conditions of share-based payment arrangement [line items]
Share-based compensation expense	$ 1.6	5.5
Stock options [member] | Calyxt Inc. [member]
Disclosure of terms and conditions of share-based payment arrangement [line items]
Vesting period, years	6 years
Share-based compensation expense	$ 0.4	2.4
Warrants [member]
Disclosure of terms and conditions of share-based payment arrangement [line items]
Share-based compensation expense	0	0.2
S A free shares [member]
Disclosure of terms and conditions of share-based payment arrangement [line items]
Share-based compensation expense	$ 3	0.1
Vesting description	The free shares granted prior to 2018 are subject to a two-year vesting period and additional two-year holding period for French residents and four-years vesting period for foreign residents. The free shares granted in 2018 and after are subject to a one-year vesting and additional one-year vesting period for French residents and two-years vesting period for foreign residents.
Dividend yield	0.00%
Restricted Stock Unit [Member]
Disclosure of terms and conditions of share-based payment arrangement [line items]
Share based payment expense		$ 1
Gain on forfeiture of shares	$ 0.6

Non-cash share-based compensa_4

Non-cash share-based compensation - Summary of assumptions Vesting Details (Detail) - Equity awards [member]	6 Months Ended
	Jun. 30, 2021shares€ / shares	Jun. 30, 2020shares€ / shares
Disclosure of terms and conditions of share-based payment arrangement [line items]
Weighted-Average fair values of stock options granted	€ 5.76	€ 7
Risk-free interest rate	0.00%	0.00%
Share entitlement per options | shares	1	1
Expected term (in years)	6.15	6.15
Vesting conditions	Service	Service
Vesting period	Graded	Graded
Bottom of Range [member]
Disclosure of terms and conditions of share-based payment arrangement [line items]
Exercise price	€ 14.36	€ 8.27
Grant date share fair value	€ 12.69	€ 9.14
Expected volatility	59.90%	61.30%
Top of Range [member]
Disclosure of terms and conditions of share-based payment arrangement [line items]
Exercise price	€ 19.44	€ 15.84
Grant date share fair value	€ 16.54	€ 15.76
Expected volatility	60.10%	62.80%

Non-cash share-based compensa_5

Non-cash share-based compensation - Summary of Information on Stock Option Activity (Detail) - Stock options [member]	6 Months Ended		12 Months Ended
	Jun. 30, 2021EUR (€)	Jun. 30, 2021USD ($)	Dec. 31, 2020EUR (€)Agreement	Dec. 31, 2020USD ($)Agreement	Dec. 31, 2019EUR (€)	Dec. 31, 2019USD ($)
Disclosure Of Number And Weighted Average Exercise Prices Of Share Options and awards [Line Items]
Equity outstanding, beginning balance	8,002,398	8,002,398	6,922,172	6,922,172
Option exercisable, granted	0	0	0	0
Option exercisable, exercised	0	0	0	0
Option exercisable, forfeited or expired	0	0	0	0
Equity outstanding, ending balance	7,750,761	7,750,761	8,002,398	8,002,398	6,922,172	6,922,172
Weighted- average exercise price per share, beginning balance | €	€ 25.28		€ 26.30
Weighted- average exercise price per share, granted | €	0		0
Weighted- average exercise price per share, exercised | €	0		0
Weighted- average exercise price per share, forfeited or expired | €	0		0
Weighted- average exercise price per share, ending balance | €	€ 25.34		€ 25.28		€ 26.30
Equity outstanding, beginning balance	9,486,657	9,486,657	9,672,382	9,672,382
Option outstanding, granted	955,485	955,485	479,000	479,000
Option outstanding, exercised	(253,494)	(253,494)	(291,053)	(291,053)
Option outstanding, forfeited or expired	(535,638)	(535,638)	(373,672)	(373,672)
Equity outstanding, ending balance	9,653,010	9,653,010	9,486,657	9,486,657	9,672,382	9,672,382
Weighted average exercise price per share, beginning balance | €	€ 23.97		€ 24.22
Weighted average exercise price per share, granted | €	19.32		12.54
Weighted average exercise price per share, exercised | €	18.49		17.86
Weighted average exercise price per share, forfeited or expired | €	19.81		20.61
Weighted average exercise price per share, ending balance | €	€ 23.88		€ 23.97		€ 24.22
Remaining Average Useful Life	5.8y	5.8y	5.9y	5.9y	6.8y	6.8y
Calyxt Inc. [member]
Disclosure Of Number And Weighted Average Exercise Prices Of Share Options and awards [Line Items]
Equity outstanding, beginning balance	2,347,663	2,347,663	1,789,567	1,789,567
Option exercisable, granted
Option exercisable, exercised
Option exercisable, forfeited or expired
Equity outstanding, ending balance	2,412,501	2,412,501	2,347,663	2,347,663	1,789,567	1,789,567
Weighted- average exercise price per share, beginning balance | $		$ 10.15		$ 8.73
Weighted- average exercise price per share, granted | $
Weighted- average exercise price per share, exercised | $
Weighted- average exercise price per share, forfeited or expired | $
Weighted- average exercise price per share, ending balance | $		$ 10.49		$ 10.15		$ 8.73
Equity outstanding, beginning balance	4,621,173	4,621,173	4,481,359	4,481,359
Option outstanding, granted	456,959	456,959	887,765	887,765
Option outstanding, exercised	(61,372)	(61,372)	(58,575)	(58,575)
Option outstanding, forfeited or expired	(550,110)	(550,110)	(689,376)	(689,376)
Equity outstanding, ending balance	4,466,650	4,466,650	4,621,173	4,621,173	4,481,359	4,481,359
Weighted average exercise price per share, beginning balance | $		$ 10.30		$ 11.73
Weighted average exercise price per share, granted | $		5.71		4.67
Weighted average exercise price per share, exercised | $		3.70		3.60
Weighted average exercise price per share, forfeited or expired | $		10.57		12.89
Weighted average exercise price per share, ending balance | $		$ 9.89		$ 10.30		$ 11.73
Remaining Average Useful Life	5.8y	5.8y	6.2y	6.2y	6.8y	6.8y

Non-cash share-based compensa_6

Non-cash share-based compensation - Summary of Information on Warrants Activity (Detail) - Warrants [member]	6 Months Ended	12 Months Ended
	Jun. 30, 2021EUR (€)	Dec. 31, 2020EUR (€)	Dec. 31, 2019EUR (€)
Disclosure Of Number And Weighted Average Exercise Prices Of Share Options and awards [Line Items]
Equity outstanding, beginning balance	899,225	852,260
Warrants exercisable, granted	0	0
Warrants exercisable, exercised	0	0
Warrants exercisable, forfeited or expired	0	0
Equity outstanding, ending balance	896,225	899,225	852,260
Weighted- average exercise price per share, beginning balance	€ 27.15	€ 35.35
Weighted- average exercise price per share, granted	0	0
Weighted- average exercise price per share, exercised		0
Weighted- average exercise price per share, forfeited or expired	0	0
Weighted- average exercise price per share, ending balance	€ 27.18	€ 27.15	€ 35.35
Equity outstanding, beginning balance	899,225	918,927
Warrants outstanding, granted	0	0
Warrants outstanding, exercised	(3,000)	(19,702)
Warrants outstanding, forfeited or expired	0	0
Equity outstanding, ending balance	896,225	899,225	918,927
Weighted average exercise price per share, beginning balance	€ 27.15	€ 35.12
Weighted average exercise price per share, granted	0	0
Weighted average exercise price per share, exercised	18.68	8.28
Weighted average exercise price per share, forfeited or expired	0	0
Weighted average exercise price per share, ending balance	€ 27.18	€ 27.15	€ 35.12
Remaining Average Useful Life	4.9y	5.3y	6.9y

Non-cash share-based compensa_7

Non-cash share-based compensation - Summary of Number of Shares Outstanding and Weighted Average Grant Date Fair Value (Detail) - S A free shares [member]	6 Months Ended	12 Months Ended
	Jun. 30, 2021EUR (€)	Dec. 31, 2020EUR (€)
Disclosure of terms and conditions of share-based payment arrangement [line items]
Number of equity outstanding, beginning balance	629,650	67,000
Number of free shares outstanding, granted	332,041	591,685
Number of free shares outstanding, vested	(9,000)	(3,000)
Number of free shares outstanding, cancelled	(90,640)	(26,035)
Number of equity outstanding, ending balance	862,051	629,650
Weighted average grant date fair value, beginning balance	€ 19.59	€ 13.98
Weighted average grant date fair Value, granted	12.78	20.10
Weighted average grant date fair value, vested	17.45	23.84
Weighted average grant date fair Value, cancelled	16.32	16.45
Weighted average grant date fair value, ending balance	€ 17.33	€ 19.59

Non-cash share-based compensa_8

Non-cash share-based compensation - Summary of Number of Shares Outstanding and Weighted Average Grant Date Fair Value (Parenthetical) (Detail) - 2018 Stock Option Plan - shares	1 Months Ended
	Mar. 31, 2021	Oct. 31, 2020
Disclosure of terms and conditions of share-based payment arrangement [line items]
Share based arrangement number of other equity instruments granted	330,041	423,285
Minimum vesting period	3 years	3 years
Non-market performance vesting conditions	103,000

Non-cash share-based compensa_9

Non-cash share-based compensation - Calyxt Equity Summary of assumptions Vesting Details (Detail) - Calyxt Inc. [member] - Stock options [member]	6 Months Ended
	Jun. 30, 2021shares$ / shares	Jun. 30, 2020shares$ / shares
Disclosure of terms and conditions of share-based payment arrangement [line items]
Weighted-Average fair values of stock options granted | $ / shares	$ 4.54	$ 5.19
Assumptions:
Risk-free interest rate		1.70%
Share entitlement per options | shares	1	1
Expected volatility		77.40%
Expected term (in years)		6.9
Vesting conditions	Service	Service
Vesting period	Graded	Graded
Bottom of Range [member]
Assumptions:
Risk-free interest rate	0.60%
Expected volatility	80.10%
Expected term (in years)	5.5
Top of Range [member]
Assumptions:
Risk-free interest rate	1.10%
Expected volatility	82.00%
Expected term (in years)	6.5

Non-cash share-based compens_10

Non-cash share-based compensation - Summary of Number of Shares Outstanding and Weighted Average Grant Date Fair Value Calyxt (Detail) - RSU Calyxt 2017 [member] - Calyxt Inc. [member]	6 Months Ended
	Jun. 30, 2021USD ($)
Disclosure of terms and conditions of share-based payment arrangement [line items]
Number of equity outstanding, beginning balance	547,807
Number of restricted stock units outstanding, granted	234,504
Number of restricted stock units outstanding, vested	(69,323)
Number of restricted stock units outstanding, cancelled	(133,348)
Number of equity outstanding, ending balance	579,640
Weighted average grant date fair value, beginning balance	$ 9.49
Weighted average grant date fair Value, granted	5.61
Weighted average grant date fair value, vested	9.25
Weighted average grant date fair Value, cancelled	12.49
Weighted average grant date fair value, ending balance	$ 7.26

Non-cash share-based compens_11

Non-cash share-based compensation - Detailed Description Inputs Stock Options Granted Performance Stock (Detail) - Performance Stock Unit [Member] - Calyxt [Member]	Jun. 28, 2019yr$ / shares
Disclosure Description Of Inputs Stock Options Granted Performance Stock [Line Items]
Estimated fair values of performance stock units granted | $ / shares	$ 7.06
Assumptions:
Risk-free interest rate	1.71%
Expected volatility	75.00%
Expected term (in years) | yr	3

Non-cash share-based compens_12

Non-cash share-based compensation - Detailed Disclosure Detail Of Stock Unit Activity Performance Stock (Detail) - Performance Stock Unit [Member] - Calyxt [Member]	6 Months Ended
	Jun. 30, 2021USD ($)shares
Disclosure Detail Of Stock Unit Activity Performance Stock [Line Items]
Number of equity outstanding, beginning balance | shares	311,667
Number of performance stock units outstanding, Granted | shares	0
Number of performance stock units outstanding, Vested | shares	0
Number of performance stock units outstanding, Cancelled | shares	(166,667)
Number of equity outstanding, ending balance | shares	145,000
Weighted average grant date fair value, beginning balance | $	$ 7.06
Weighted average grant date fair Value, granted | $	0
Weighted average grant date fair value, vested | $	0
Weighted average grant date fair Value, cancelled | $
Weighted average grant date fair value, ending balance | $	$ 7.06

Earnings Per Share - Details of

Earnings Per Share - Details of Earnings Per Share (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Earnings per share [abstract]
Net income (loss) attributable to shareholders of Cellectis ($ in thousands)	$ (39,919)	$ (32,263)	$ (51,787)	$ (12,221)
Adjusted weighted average number of outstanding shares, used to calculate both basic and diluted net result per share	45,461,310	42,472,490	44,163,914	42,469,080
Basic net income (loss) attributable to shareholders of Cellectis per share ( $ /share)	$ (0.88)	$ (0.76)	$ (1.17)	$ (0.29)
Diluted net income (loss) attributable to shareholders of Cellectis per share ( $ /share)	$ (0.88)	$ (0.76)	$ (1.17)	$ (0.29)

Provisions - Summary of Provisi

Provisions - Summary of Provisions for Termination Benefits (Detail) $ in Thousands	6 Months Ended
	Jun. 30, 2021USD ($)
Disclosure of other provisions [line items]
Additions	$ 1,230
Amounts used during the period	(296)
Pension, Reversals	(330)
OCI	(739)
Ending balance	5,007
Restated [member]
Disclosure of other provisions [line items]
Beginning balance	5,141
Pension [member]
Disclosure of other provisions [line items]
Pension, Additions	299
OCI	(699)
Ending balance	3,610
Pension [member] | Restated [member]
Disclosure of other provisions [line items]
Beginning balance	4,010
Loss on Contract [member]
Disclosure of other provisions [line items]
Loss on contract, Additions	0
Loss on contract, Amounts used during the period	0
Loss on contract, Ending balance	0
Employee Litigation and Severance [member]
Disclosure of other provisions [line items]
Employee litigation and severance, Additions	30
Employee litigation and severance, Amounts used during the period	(101)
Employee litigation and severance, Reversals	(84)
Employee litigation and severance, OCI	(15)
Employee litigation and severance, Ending balance	391
Employee Litigation and Severance [member] | Restated [member]
Disclosure of other provisions [line items]
Employee litigation and severance, Beginning balance	560
Commercial litigation [member]
Disclosure of other provisions [line items]
Additions	900
Pension, Reversals	(400)
Commercial litigation, Additions	901
Commercial litigation, Amounts used during the period	(194)
Commercial litigation, Reversals	(246)
Commercial litigation, OCI	(25)
Commercial litigation, Ending balance	1,006
Commercial litigation [member] | Restated [member]
Disclosure of other provisions [line items]
Commercial litigation, Beginning balance	$ 571

Provisions - Additional Informa

Provisions - Additional Information (Detail) $ in Thousands	6 Months Ended
	Jun. 30, 2021USD ($)
Disclosure of provisions [line items]
Provisions for termination benefits	$ 1,230
Provisions reversed for termination benefits	(330)
Pension service cost [member]
Disclosure of provisions [line items]
Provisions for termination benefits	300
Commercial litigation [member]
Disclosure of provisions [line items]
Provisions for termination benefits	900
Provisions reversed for termination benefits	(400)
Settlement of Employee Litigation [Member]
Disclosure of provisions [line items]
Provisions reversed for termination benefits	$ (200)

Commitments - Schedule of Commi

Commitments - Schedule of Commitments (Detail) $ in Thousands	Jun. 30, 2021USD ($)
Disclosure of contingent liabilities [line items]
Total commitments	$ 29,442
License Agreements [member]
Disclosure of contingent liabilities [line items]
Total commitments	18,345
Manufacturing Agreements [member]
Disclosure of contingent liabilities [line items]
Total commitments	947
Other Agreements [member]
Disclosure of contingent liabilities [line items]
Total commitments	6,839
IT Licensing Agreements [Member]
Disclosure of contingent liabilities [line items]
Total commitments	1,335
Clinical & R&D agreements [member]
Disclosure of contingent liabilities [line items]
Total commitments	288
Construction agreements [member]
Disclosure of contingent liabilities [line items]
Total commitments	1,687
Less than One Year [member]
Disclosure of contingent liabilities [line items]
Total commitments	11,665
Less than One Year [member] | License Agreements [member]
Disclosure of contingent liabilities [line items]
Total commitments	1,530
Less than One Year [member] | Manufacturing Agreements [member]
Disclosure of contingent liabilities [line items]
Total commitments	930
Less than One Year [member] | Other Agreements [member]
Disclosure of contingent liabilities [line items]
Total commitments	6,839
Less than One Year [member] | IT Licensing Agreements [Member]
Disclosure of contingent liabilities [line items]
Total commitments	445
Less than One Year [member] | Clinical & R&D agreements [member]
Disclosure of contingent liabilities [line items]
Total commitments	234
Less than One Year [member] | Construction agreements [member]
Disclosure of contingent liabilities [line items]
Total commitments	1,687
1-3 years [member]
Disclosure of contingent liabilities [line items]
Total commitments	4,022
1-3 years [member] | License Agreements [member]
Disclosure of contingent liabilities [line items]
Total commitments	3,060
1-3 years [member] | Manufacturing Agreements [member]
Disclosure of contingent liabilities [line items]
Total commitments	18
1-3 years [member] | IT Licensing Agreements [Member]
Disclosure of contingent liabilities [line items]
Total commitments	890
1-3 years [member] | Clinical & R&D agreements [member]
Disclosure of contingent liabilities [line items]
Total commitments	54
3-5 years [member]
Disclosure of contingent liabilities [line items]
Total commitments	3,060
3-5 years [member] | License Agreements [member]
Disclosure of contingent liabilities [line items]
Total commitments	3,060
More than Five Years [member]
Disclosure of contingent liabilities [line items]
Total commitments	10,695
More than Five Years [member] | License Agreements [member]
Disclosure of contingent liabilities [line items]
Total commitments	$ 10,695

Commitments - Additional Inform

Commitments - Additional Information (Detail) - Calyxt Inc [member] $ in Millions	6 Months Ended
	Jun. 30, 2021USD ($)
Disclosure of contingent liabilities [line items]
Long-term purchase commitment	$ 6.8
Gain (loss) on hedge ineffectiveness	(1)
Notional amount	$ 8