Constellium SE (CSTM) 6-K 23 Jul 24 2024 Q2 Second Quarter Report Financial data

Cover

Cover	6 Months Ended
	Jun. 30, 2024
Cover [Abstract]
Document Type	6-K
Entity Registrant Name	Constellium SE
Amendment Flag	false
Document Period End Date	Jun. 30, 2024
Document Fiscal Year Focus	2024
Document Fiscal Period Focus	Q2
Entity Central Index Key	0001563411
Current Fiscal Year End Date	--12-31

UNAUDITED INTERIM CONSOLIDATED

UNAUDITED INTERIM CONSOLIDATED INCOME STATEMENT - EUR (€) € in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Profit or loss [abstract]
Revenue	€ 1,795	€ 1,950	€ 3,526	€ 3,906
Cost of sales	(1,605)	(1,737)	(3,175)	(3,532)
Gross profit	190	213	351	374
Selling and administrative expenses	(74)	(80)	(149)	(151)
Research and development expenses	(13)	(13)	(28)	(26)
Other gains and losses - net	24	(41)	11	(56)
Income from operations	127	79	185	141
Finance costs - net	(32)	(35)	(65)	(70)
Income before tax	95	44	120	71
Income tax expense	(24)	(12)	(32)	(17)
Net income	71	32	88	54
Net income attributable to:
Equity holders of Constellium	71	31	87	51
Non-controlling interests	0	1	1	3
Net income	€ 71	€ 32	€ 88	€ 54
Earnings per share attributable to the equity holders of Constellium (in Euros)
Basic (in EUR per share)	€ 0.48	€ 0.21	€ 0.59	€ 0.35
Diluted (in EUR per share)	€ 0.48	€ 0.21	€ 0.58	€ 0.34
Weighted average number of shares
Basic (in shares)	146,271,938	146,543,148	146,534,099	145,428,562
Diluted (in shares)	149,040,318	148,190,856	149,670,265	148,190,856

UNAUDITED INTERIM CONSOLIDATE_2

UNAUDITED INTERIM CONSOLIDATED STATEMENT OF COMPREHENSIVE INCOME / (LOSS) - EUR (€) € in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Statement of comprehensive income [abstract]
Net income	€ 71	€ 32	€ 88	€ 54
Items that will not be reclassified subsequently to the consolidated income statement
Remeasurement on post-employment benefit obligations	11	5	34	4
Income tax on remeasurement on post-employment benefit obligations	(3)	(3)	(6)	(2)
Items that may be reclassified subsequently to the consolidated income statement
Cash flow hedges	(2)	1	(4)	4
Income tax on cash flow hedges	1	0	1	(1)
Currency translation differences	9	0	22	(13)
Other comprehensive income / (loss)	16	3	47	(8)
Total comprehensive income	87	35	135	46
Attributable to:
Equity holders of Constellium	87	34	134	44
Non-controlling interests	0	1	1	2
Total comprehensive income	€ 87	€ 35	€ 135	€ 46

UNAUDITED INTERIM CONSOLIDATE_3

UNAUDITED INTERIM CONSOLIDATED STATEMENT OF FINANCIAL POSITION - EUR (€)	Jun. 30, 2024	Dec. 31, 2023
Current assets
Cash and cash equivalents	€ 213,000,000	€ 202,000,000
Trade receivables and other	693,000,000	490,000,000
Inventories	1,134,000,000	1,098,000,000
Other financial assets	22,000,000	30,000,000
Total current assets	2,062,000,000	1,820,000,000
Non-current assets
Property, plant and equipment	2,084,000,000	2,047,000,000
Goodwill	477,000,000	462,000,000
Intangible assets	45,000,000	47,000,000
Deferred tax assets	234,000,000	252,000,000
Trade receivables and other	35,000,000	31,000,000
Other financial assets	2,000,000	2,000,000
Total non-current assets	2,877,000,000	2,841,000,000
Total Assets	4,939,000,000	4,661,000,000
Current liabilities
Trade payables and other	1,431,000,000	1,263,000,000
Borrowings	53,000,000	54,000,000
Other financial liabilities	30,000,000	34,000,000
Income tax payable	19,000,000	19,000,000
Provisions	19,000,000	18,000,000
Total current liabilities	1,552,000,000	1,388,000,000
Non-current liabilities
Trade payables and other	68,000,000	59,000,000
Borrowings	1,842,000,000	1,814,000,000
Other financial liabilities	11,000,000	8,000,000
Pension and other post-employment benefit obligations	380,000,000	411,000,000
Provisions	86,000,000	89,000,000
Deferred tax liabilities	27,000,000	28,000,000
Total non-current liabilities	2,414,000,000	2,409,000,000
Total Liabilities	3,966,000,000	3,797,000,000
Equity
Share capital	2,936,397.68	3,000,000
Share premium	420,000,000	420,000,000
Retained earnings and other reserves	529,000,000	420,000,000
Equity attributable to equity holders of Constellium	952,000,000	843,000,000
Non-controlling interests	21,000,000	21,000,000
Total Equity	973,000,000	864,000,000
Total Equity and Liabilities	€ 4,939,000,000	€ 4,661,000,000

UNAUDITED INTERIM CONSOLIDATE_4

UNAUDITED INTERIM CONSOLIDATED STATEMENT OF CHANGES IN EQUITY - EUR (€) € in Millions	Total	Total	Share capital	Share premium	Treasury shares	Re- measurement	Cash flow hedges	Foreign currency translation reserve	Other reserves	Retained earnings	Non-controlling interests
Beginning balance at Dec. 31, 2022	€ 752	€ 731	€ 3	€ 420		€ 28	€ (10)	€ 41	€ 101	€ 148	€ 21
Net income	54	51								51	3
Other comprehensive income / (loss)	(8)	(7)				2	3	(12)			(1)
Total comprehensive income	46	44				2	3	(12)		51	2
Share-based compensation	10	10							10
Transactions with non-controlling interests	(2)										(2)
Ending balance at Jun. 30, 2023	806	785	3	420		30	(7)	29	111	199	21
Beginning balance at Dec. 31, 2022	752	731	3	420		28	(10)	41	101	148	21
Net income	129	125								125	4
Other comprehensive income / (loss)	(34)	(33)				(14)	6	(25)			(1)
Total comprehensive income	95	92				(14)	6	(25)		125	3
Share-based compensation	20	20							20
Other	0					(1)				1
Transactions with non-controlling interests	(3)										(3)
Ending balance at Dec. 31, 2023	864	843	3	420	€ 0	13	(4)	16	121	274	21
Net income	88	87								87	1
Other comprehensive income / (loss)	47	47				28	(3)	22
Total comprehensive income	135	134				28	(3)	22		87	1
Share-based compensation	12	12							12
Reduction of issued capital	(37)				(37)
Allocation of treasury shares to share-based compensation plan vested	0				27				(27)
Transactions with non-controlling interests	(1)										(1)
Ending balance at Jun. 30, 2024	€ 973	€ 952	€ 3	€ 420	€ (10)	€ 41	€ (7)	€ 38	€ 106	€ 361	€ 21

UNAUDITED INTERIM CONSOLIDATE_5

UNAUDITED INTERIM CONSOLIDATED STATEMENT OF CASH FLOWS - EUR (€) € in Millions	6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023
Statement of cash flows [abstract]
Net income	€ 88	€ 54
Adjustments
Depreciation and amortization	145	144
Pension and other post-employment benefits service costs	10	11
Finance costs - net	65	70
Income tax expense	32	17
Unrealized (gains) / losses on derivatives - net and from remeasurement of monetary assets and liabilities - net	(2)	28
Losses on disposal	1	6
Other - net	12	10
Change in working capital
Inventories	(23)	150
Trade receivables	(186)	(224)
Trade payables	153	(14)
Other	10	6
Change in provisions	(2)	(2)
Pension and other post-employment benefits paid	(20)	(19)
Interest paid	(56)	(63)
Income tax paid	(21)	(7)
Net cash flows from operating activities	206	167
Purchases of property, plant and equipment	(146)	(134)
Property, plant and equipment grants received	7	1
Net cash flows used in investing activities	(139)	(133)
Repurchase of ordinary shares	(37)	0
Repayments of long-term borrowings	(4)	(5)
Net change in revolving credit facilities and short-term borrowings	0	7
Lease repayments	(13)	(16)
Transactions with non-controlling interests	(3)	(3)
Other financing activities	1	(2)
Net cash flows used in financing activities	(56)	(19)
Net increase in cash and cash equivalents	11	15
Cash and cash equivalents - beginning of year	202	166
Transfer of cash and cash equivalents from assets classified as held for sale	0	(1)
Effect of exchange rate changes on cash and cash equivalents	0	(2)
Cash and cash equivalents - end of period	€ 213	€ 178

GENERAL INFORMATION

GENERAL INFORMATION	6 Months Ended
	Jun. 30, 2024
Disclosure of general information [abstract]
GENERAL INFORMATION	NOTE 1 - GENERAL INFORMATION Constellium is a global leader in the design and manufacture of a broad range of innovative specialty rolled and extruded aluminium products, serving primarily the packaging, aerospace and automotive end-markets. The Group has a strategic footprint of manufacturing facilities located in North America, Europe and China and operates 25 production facilities, 3 R&D centers and 3 administrative centers. The Group has approximately 12,000 employees. Constellium SE, a French Societas Europaea (SE), is the parent company of the Group. The business address (head office) of Constellium SE is located at Washington Plaza, 40-44 rue Washington, 75008 Paris, France. Unless the context indicates otherwise, when we refer to “we”, “our”, “us”, “Constellium”, the “Group” and the “Company” in this document, we are referring to Constellium SE and its subsidiaries.

SUMMARY OF SIGNIFICANT ACCOUNTI

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES	6 Months Ended
	Jun. 30, 2024
Disclosure of summary of significant accounting policies [abstract]
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES	NOTE 2 - SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES 2.1 Basis of preparation The Unaudited Interim Condensed Consolidated Financial Statements (the "Interim Financial Statements") have been prepared in accordance with IAS 34 - Interim Financial Reporting . Accordingly, they do not include all the information and disclosures required in consolidated financial statements and should be read in conjunction with the Group’s Consolidated Financial Statements for the year ended December 31, 2023. In accordance with IAS 1- Presentation of Financial Statements , the Interim Financial Statements are prepared on the assumption that Constellium is a going concern and will continue in operation for the foreseeable future. The accounting policies adopted in the preparation of the Interim Financial Statements are consistent with those followed in the preparation of the Group’s Consolidated Financial Statements for the year ended December 31, 2023, except for the application of the effective tax rate method in accordance with IAS 34 - Interim Financial Reporting . The Interim Financial Statements are presented in millions of Euros, except when otherwise indicated. Certain reclassifications may have been made to prior year amounts to conform to the current year presentation. Amounts may not sum due to rounding. The Interim Financial Statements were authorized for issue by management on July 22, 2024. 2.2 New and amended standards and interpretations Several amendments to IFRS standards apply for the first time in 2024, but have no impact on the Interim Financial Statements of the Group. The Group has applied the mandatory exception to recognizing and disclosing information about deferred tax assets and liabilities arising from Pillar Two income taxes. The Group has reviewed its corporate structure in light of the introduction of Pillar Two Model Rules in the jurisdictions where it operates based on the most recent tax filings and financial statements. Based on this assessment, the Group has determined that it is not subject to Pillar Two “top-up” taxes for the the six months ended June 30, 2024. The Group has not early adopted any standard, interpretation or amendment that has been issued but is not yet effective. The Group plans to adopt new standards and interpretations on their required effective dates. 2.3 Judgments in applying accounting policies and key sources of estimation uncertainty The preparation of financial statements requires management to make judgements, estimates and assumptions that affect the reported amounts of revenues, expenses, assets and liabilities, along with the accompanying disclosures and the disclosure of contingent liabilities. These judgments, estimates and assumptions are based on management’s best knowledge of the relevant facts and circumstances, giving consideration to previous experience. However, actual results may differ from the amounts included in the financial statements. In preparing these Interim Financial Statements, the significant judgments made by management in applying the Group’s accounting policies and the key sources of estimation uncertainty were the same as those applied to the Consolidated Financial Statements at and for the year ended December 31, 2023, as well as the application of the effective tax rate method for the determination of the income tax provision. 2.4 Exchange rates The following table summarizes the main exchange rates used for the preparation of the Interim Financial Statements: Average rates Closing rates Foreign exchange rate for 1 Euro Six months ended June 30, At June 30, At December 31, 2024 2023 2024 2023 U.S. Dollars USD 1.0812 1.0805 1.0705 1.1050 Swiss Francs CHF 0.9612 0.9855 0.9634 0.9260 Czech Koruna CZK 25.0118 23.6858 25.0250 24.7240

REVENUE

REVENUE	6 Months Ended
	Jun. 30, 2024
Revenue [abstract]
REVENUE	NOTE 3 - REVENUE Three months ended June 30, Six months ended June 30, (in millions of Euros) 2024 2023 2024 2023 Packaging rolled products 677 699 1,295 1,384 Automotive rolled products 296 312 583 616 Specialty and other thin-rolled products 26 34 55 70 Aerospace rolled products 244 271 507 524 Transportation, industry, defense and other rolled products 195 190 363 385 Automotive extruded products 233 251 475 511 Other extruded products 123 193 245 416 Other metal sales 2 — 3 — Total Revenue by product line 1,795 1,950 3,526 3,906 Three months ended June 30, Six months ended June 30, (in millions of Euros) 2024 2023 2024 2023 Germany 372 447 734 926 France 163 178 337 360 United Kingdom 74 67 133 128 Switzerland 20 15 36 40 Spain 80 85 171 166 Czech Republic 52 67 106 124 Other Europe 247 241 474 483 Total Europe 1,008 1,100 1,991 2,227 United States 597 716 1,185 1,389 Asia and Other Pacific 70 61 138 122 All Other 120 73 212 168 Total Revenue by destination of shipment 1,795 1,950 3,526 3,906

OPERATING SEGMENT INFORMATION

OPERATING SEGMENT INFORMATION	6 Months Ended
	Jun. 30, 2024
Disclosure of operating segments [abstract]
OPERATING SEGMENT INFORMATION	NOTE 4 - OPERATING SEGMENT INFORMATION Constellium has three reportable segments - Packaging & Automotive Rolled Products (P&ARP), Aerospace & Transportation (A&T) and Automotive Structures & Industry (AS&I) - and Holdings & Corporate (H&C) 4.1 Segment Revenue Three months ended June 30, Six months ended June 30, 2024 2023 2024 2023 (in millions of Euros) Segment revenue Inter-segment elimination External revenue Segment revenue Inter-segment elimination External revenue Segment revenue Inter-segment elimination External revenue Segment revenue Inter-segment elimination External revenue P&ARP 1,001 (2) 999 1,049 (4) 1,045 1,939 (6) 1,933 2,079 (9) 2,070 A&T 452 (13) 439 464 (2) 462 893 (23) 870 916 (7) 909 AS&I 357 (1) 356 443 — 443 721 (1) 720 926 — 926 H&C 2 — 2 — — — 3 — 3 1 — 1 Segment revenue 1,812 (17) 1,795 1,956 (6) 1,950 3,556 (30) 3,526 3,922 (16) 3,906 4.2 Segment Adjusted EBITDA and reconciliation of Segment adjusted EBITDA to Net Income Three months ended June 30, Six months ended June 30, (in millions of Euros) Notes 2024 2023 2024 2023 P&ARP 64 79 107 134 A&T 83 96 163 169 AS&I 32 39 65 82 H&C (7) (5) (13) (11) Segment Adjusted EBITDA 172 209 322 374 Metal price lag (A) 42 (30) 29 (45) Share based compensation costs 22 (6) (7) (12) (10) Depreciation and amortization 12, 13 (74) (72) (145) (144) Restructuring costs (B) 5 (3) — (3) — Unrealized gains / (losses) on derivatives 3 (20) — (28) Unrealized exchange (losses) / gains from the remeasurement of monetary assets and liabilities – net 5 — (1) 2 — Losses on disposal (C) 5 — — (1) (6) Other (D) (7) — (7) — Income from operations 127 79 185 141 Finance costs - net 7 (32) (35) (65) (70) Income before tax 95 44 120 71 Income tax expense 8 (24) (12) (32) (17) Net income 71 32 88 54 (A) Metal price lag represents the financial impact of the timing difference between when aluminium prices included within Constellium's Revenue are established and when aluminium purchase prices included in Cost of sales are established. The metal price lag will generally increase our earnings in times of rising primary aluminium prices and decrease our earnings in times of declining primary aluminium prices. The calculation of metal price lag adjustment is based on a standardized methodology applied at each of Constellium’s manufacturing sites. Metal price lag is calculated as the average value of product purchased in the period, approximated at the market price, less the value of product in inventory at the weighted average of metal purchased over time, multiplied by the quantity sold in the period. (B) For the six months ended June 30, 2024, restructuring costs amounted to €3 million and were related to cost improvement programs in Europe and in the U.S. (C) For the six months ended June 30, 2023, gains and losses on disposal costs net of transaction costs included a €5 million loss related to the sale of Constellium Ussel S.A.S. completed on February 2, 2023. (D) For the six months ended June 30, 2024, other was related to €5 million of inventory impairment as a result of flooding in Sierre and Chippis facilities at the end of June 2024 (refer to NOTE 23 - SUBSEQUENT EVENTS) as well as €2 million of costs associated with non-recurring corporate transformation projects. 4.3 Segment capital expenditures Six months ended June 30, (in millions of Euros) 2024 2023 P&ARP (74) (71) A&T (38) (37) AS&I (32) (25) H&C (2) (1) Capital expenditures (146) (134) 4.4 Segment assets (in millions of Euros) At June 30, At December 31, P&ARP 2,181 2,102 A&T 1,220 1,087 AS&I 690 673 H&C 377 313 Segment assets 4,468 4,175 Deferred income tax assets 234 252 Cash and cash equivalents 213 202 Other financial assets 24 32 Total Assets 4,939 4,661

OTHER GAINS AND LOSSES_NET

OTHER GAINS AND LOSSES—NET	6 Months Ended
	Jun. 30, 2024
Analysis of income and expense [abstract]
OTHER GAINS AND LOSSES—NET	NOTE 5 - OTHER GAINS AND LOSSES - NET Three months ended June 30, Six months ended June 30, (in millions of Euros) 2024 2023 2024 2023 Realized gains / (losses) on derivatives (A) 23 (19) 12 (23) Unrealized gains / (losses) on derivatives at fair value through profit and loss - net (A) 3 (20) — (28) Unrealized exchange (losses) / gains from the remeasurement of monetary assets and liabilities – net — (1) 2 — Restructuring costs (B) (3) — (3) — Losses on disposal (C) — — (1) (6) Other 1 (1) 1 1 Total other gains and losses - net 24 (41) 11 (56) (A) Realized and unrealized gains and losses are related to derivatives entered into with the purpose of mitigating exposure to volatility in foreign currencies and commodity prices, and that do not qualify for hedge accounting. (B) For the six months ended June 30, 2024, restructuring costs amounted to €3 million and related to cost improvement programs in Europe and in the U.S. (C)

CURRENCY GAINS _ (LOSSES)

CURRENCY GAINS / (LOSSES)	6 Months Ended
	Jun. 30, 2024
Analysis of income and expense [abstract]
CURRENCY GAINS / (LOSSES)	NOTE 6 - CURRENCY GAINS / (LOSSES) Three months ended June 30, Six months ended June 30, (in millions of Euros) Notes 2024 2023 2024 2023 Included in Revenue 17 (2) (1) (5) (2) Included in Cost of sales — — — (1) Included in Other gains and losses - net (5) (1) (13) 5 Total (7) (2) (18) 2 Realized exchange (losses) / gains on foreign currency derivatives - net 17 (4) 4 (8) 6 Unrealized losses on foreign currency derivatives - net 17 (3) (6) (12) (3) Exchange gains / (losses) from the remeasurement of monetary assets and liabilities - net — — 2 (1) Total (7) (2) (18) 2 See NOTE 16 - Financial Instruments and NOTE 17 - Financial Risk Management for further information regarding the Company’s foreign currency derivatives and hedging activities.

FINANCE COSTS_NET

FINANCE COSTS—NET	6 Months Ended
	Jun. 30, 2024
Analysis of income and expense [abstract]
FINANCE COSTS—NET	NOTE 7 - FINANCE COSTS - NET Three months ended June 30, Six months ended June 30, (in millions of Euros) 2024 2023 2024 2023 Interest expense on borrowings (A) (21) (25) (44) (49) Interest expense on leases (2) (2) (4) (5) Interest cost on pension and other benefits (5) (4) (8) (8) Expenses on factoring arrangements (5) (5) (9) (10) Realized and unrealized gains / (losses) on debt derivatives at fair value (B) — 4 (1) 4 Realized and unrealized exchange gains / (losses) on financing activities - net (B) 1 (3) 1 (2) Other finance expenses (1) (1) (2) (2) Capitalized borrowing costs (C) 1 1 2 2 Finance expenses (32) (35) (65) (70) Finance costs - net (32) (35) (65) (70) (A) For the six months ended June 30, 2024 and 2023 , interest expense on borrowings inc luded €38 million of interest, and €2 million of am ortization of arrangement fees related to Constellium SE Senior Notes. (B) The Group hedges the dollar exposure, relating to the principal of its Constellium SE U.S. Dollar Senior Notes, for the portion that has not been used to finance directly or indirectly U.S. Dollar functional currency entities. Changes in the fair value of these hedging derivatives are recognized within Finance costs – net in the Interim Income Statement. (C) Borrowing costs directly attributable to the construction of assets are capitalized. The capitalization rate w as 5% for the six months ended June 30, 2024 and 2023.

INCOME TAX

INCOME TAX	6 Months Ended
	Jun. 30, 2024
Income Taxes [Abstract]
INCOME TAX	NOTE 8 - INCOME TAX Income tax expense for interim periods is recognized based on the best estimate of the weighted average annual income tax rate expected for the full year, adjusted for the tax effect of certain items recognized in full in the interim period. The tax rate applied at June 30, 2024 was impacted by changes in the allocation of income or loss by country.

CASH AND CASH EQUIVALENTS

CASH AND CASH EQUIVALENTS	6 Months Ended
	Jun. 30, 2024
Cash and cash equivalents [abstract]
CASH AND CASH EQUIVALENTS	NOTE 9 - CASH AND CASH EQUIVALENTS Cash at bank and on hand at June 30, 2024 amounted to €213 million and included €20 million held by subsidiaries that operate in countries where capital control restrictions prevent these balances from being immediately available for general use by the other entities within the Group. At December 31, 2023, the amount subject to these restrictions was €22 million.

INVENTORIES

INVENTORIES	6 Months Ended
	Jun. 30, 2024
Subclassifications of assets, liabilities and equities [abstract]
INVENTORIES	NOTE 11 - INVENTORIES (in millions of Euros) At June 30, At December 31, Finished goods 234 260 Work in progress 625 537 Raw materials 203 231 Stores and supplies 128 123 Inventories write down (56) (53) Total inventories 1,134 1,098

PROPERTY, PLANT AND EQUIPMENT

PROPERTY, PLANT AND EQUIPMENT	6 Months Ended
	Jun. 30, 2024
Property, plant and equipment [abstract]
PROPERTY, PLANT AND EQUIPMENT	NOTE 12 - PROPERTY, PLANT AND EQUIPMENT (in millions of Euros) Land and Property Rights Buildings Machinery and Equipment Construction Work in Progress Other Total Net balance at January 1, 2024 25 379 1,381 251 11 2,047 Additions 1 3 36 114 2 156 Disposals — — (2) — — (2) Depreciation expense (1) (17) (119) — (4) (141) Transfer and other changes 1 4 38 (46) 2 (1) Effect of changes in foreign exchange rates — 3 20 2 — 25 Net balance at June 30, 2024 26 372 1,354 321 11 2,084 Cost 47 672 3,198 333 55 4,305 Less accumulated depreciation and impairment (21) (300) (1,844) (12) (44) (2,221) Net balance at June 30, 2024 26 372 1,354 321 11 2,084 Right-of-use assets Right-of-use assets have been included in the same line item as that in which a corresponding owned asset would be presented. (in millions of Euros) Buildings Machinery and Equipment Other Total Net balance at January 1, 2024 103 38 — 141 Additions 3 8 — 11 Depreciation expense (6) (6) — (12) Net balance at June 30, 2024 100 40 — 140 Cost 172 107 — 279 Less accumulated depreciation and impairment (72) (67) — (139) Net balance at June 30, 2024 100 40 — 140 The total expense relating to short-term leases, low value asset leases and variable lease payments that are still recognized as operating expens es was €9 million and €8 million for the six months ended June 30, 2024 and 2023, respectively.

INTANGIBLE ASSETS AND GOODWILL

INTANGIBLE ASSETS AND GOODWILL	6 Months Ended
	Jun. 30, 2024
Intangible assets and goodwill [abstract]
INTANGIBLE ASSETS AND GOODWILL	NOTE 13 - INTANGIBLE ASSETS AND GOODWILL (in millions of Euros) Technology Computer Software Customer relationships Work in Progress Other Total Intangible Assets Goodwill Net balance at January 1, 2024 16 13 12 3 3 47 462 Additions — — — 1 — 1 — Amortization expense (1) (2) — (1) — (4) — Effect of changes in foreign exchange rates 1 — — — — 1 15 Net balance at June 30, 2024 16 11 12 3 3 45 477 Cost 92 88 42 4 4 230 477 Less accumulated depreciation and impairment (76) (77) (30) (1) (1) (185) — Net balance at June 30, 2024 16 11 12 3 3 45 477

TRADE PAYABLES AND OTHER

TRADE PAYABLES AND OTHER	6 Months Ended
	Jun. 30, 2024
Trade and other payables [abstract]
TRADE PAYABLES AND OTHER	NOTE 14 - TRADE PAYABLES AND OTHER At June 30, At December 31, (in millions of Euros) Non-current Current Non-current Current Trade payables — 1,099 — 931 Fixed assets payables — 41 — 35 Employees' entitlements — 195 — 211 Taxes payable other than income tax — 32 — 15 Contract liabilities and other liabilities to customers 31 54 29 62 Other payables 37 10 30 9 Total other 68 332 59 332 Total trade payables and other 68 1,431 59 1,263 Contract liabilities and other liabilities to customers At June 30, At December 31, (in millions of Euros) Non-current Current Non-current Current Deferred tooling revenue 30 — 28 — Advance payment from customers — 12 — 7 Unrecognized variable consideration (A) 1 42 1 55 Total contract liabilities and other liabilities to customers 31 54 29 62 (A) Unrecognized variable consideration consists of expected volume rebates, discounts, incentives, refunds penalties and price concessions. Revenue of €24 million that related to contract liabilities at January 1, 2024 was recognized in the six months ended June 30, 2024. There was €15 million of deferred revenue generated in the six months ended June 30, 2024. Revenue of €11 million that related to contract liabilities at January 1, 2023 was recognized in the six months ended June 30, 2023. There was €27 million of deferred revenue gene rated in the six months ended June 30, 2023.

BORROWINGS

BORROWINGS	6 Months Ended
	Jun. 30, 2024
Borrowings [abstract]
BORROWINGS	NOTE 15 - BORROWINGS 15.1 Analysis by nature At June 30, At December 31, (in millions of Euros) Nominal Value in Currency Nominal rate Nominal Value in Euros (Arrange-ment fees) Accrued interests Carrying value Carrying Senior Unsecured Notes (A) Issued November 2017 and due 2026 $ 250 5.875% 234 (1) 5 238 230 Issued November 2017 and due 2026 € 400 4.250% 400 (2) 6 404 404 Issued June 2020 and due 2028 $ 325 5.625% 303 (3) 1 301 291 Issued February 2021 and due 2029 $ 500 3.750% 467 (5) 4 466 452 Issued June 2021 and due 2029 € 300 3.125% 300 (3) 4 301 300 Lease liabilities 151 — 1 152 154 Other loans (B) 33 — — 33 37 Total Borrowings 1,888 (14) 21 1,895 1,868 Of which non-current 1,842 1,814 Of which current 53 54 (A) The Senior Unsecured Notes were issued by Constellium SE and are guaranteed by certain subsidiaries. (B) Other loans inclu de €28 million o f financial liabilities relating to the sale and leaseback of assets that were considered to be financing arrangements in substance. 15.2 Undrawn credit facilities and overdraft arrangements At June 30, 2024, the Group had a $500 million Pan-U.S. ABL facility in place. This secured asset-based credit facility matures in April 2026. The Group also had a €100 million French inventory facility in place. This committed asset-based credit facility matures in April 2025 and was undrawn at June 30, 2024. The Group also uses a €75 million Money Market facility, as well as overdraft agreements with its commercial banks for cash management purposes. These arrangements are uncommitted and were undrawn at June 30, 2024. 15.3 Covenants The Group was in compliance with all applicable debt covenants at June 30, 2024 and December 31, 2023 and for the six months ended June 30, 2024. 15.4 Movements in borrowings (in millions of Euros) At June 30, At December 31, At January 1, 1,868 2,056 Cash flows Repayments of long-term borrowings (A) (4) (53) Net change in revolving credit facilities and short-term borrowings (B) — (83) Lease repayments (13) (37) Non-cash changes Movement in accrued interest — (1) Changes in leases and other loans 9 24 Deferred arrangement fees 2 4 Effects of changes in foreign exchange rates 33 (42) At the end of the period 1,895 1,868 (A) For the twelve months ended December 31, 2023, repayments of long-term borrowings included the redemption of $50 million out of the $300 million outstanding aggregate principal amount of the 5.875% Senior Notes due 2026 on July 20, 2023. (B) For the twelve months ended December 31, 2023 , the net change in revolving credit facilities and short-term borrowings included mainly the repayment under the Pan-U.S. ABL. 15.5 Currency concentration (in millions of Euros) At June 30, At December 31, 2023 U.S. Dollar 1,044 1,012 Euro 845 849 Other currencies 6 7 Total borrowings 1,895 1,868

FINANCIAL INSTRUMENTS

FINANCIAL INSTRUMENTS	6 Months Ended
	Jun. 30, 2024
Disclosure of detailed information about financial instruments [abstract]
FINANCIAL INSTRUMENTS	NOTE 16 - FINANCIAL INSTRUMENTS 16.1 Financial assets and liabilities by categories At June 30, At December 31, (in millions of Euros) Notes At amortized cost At fair value through profit and loss At fair value through OCI Total At amortized cost At fair value through profit and loss At fair value through OCI Total Cash and cash equivalents 9 213 — — 213 202 — — 202 Trade receivables 10 — — 578 578 — — 386 386 Other financial assets — 24 — 24 — 31 1 32 Total 213 24 578 815 202 31 387 620 At June 30, At December 31, (in millions of Euros) Notes At amortized cost At fair value through profit and loss At fair value through OCI Total At amortized cost At fair value through profit and loss At fair value through OCI Total Trade payables and fixed asset payables 14 1,140 — — 1,140 966 — — 966 Borrowings 15 1,895 — — 1,895 1,868 — — 1,868 Other financial liabilities — 31 10 41 — 35 7 42 Total 3,035 31 10 3,076 2,834 35 7 2,876 16.2 Fair values The carrying value of the Group’s borrowings at maturity is the redemption value. The fair values of Constellium SE Senior Notes issued in November 2017, June 2020, February 2021 and June 2021 are 99.5%, 97.8%, 90.4% and 93.4%, respectively, of the nominal values and amount to €631 million, €297 million, €422 million and €280 million, respectiv ely, at June 30, 2024. All derivatives are presented at fair value in the Interim Statement of Financial Position. The fair values of trade receivables, other financial assets and liabilities approximate their carrying values, as a result of their liquidity or short maturity. At June 30, At December 31, (in millions of Euros) Non-current Current Total Non-current Current Total Aluminium and premium derivatives 2 15 17 1 17 18 Other commodity derivatives — 4 4 — 1 1 Currency commercial derivatives — 3 3 1 10 11 Currency net debt derivatives — — — — 2 2 Other financial assets - derivatives 2 22 24 2 30 32 Aluminium and premium derivatives 1 6 7 1 9 10 Energy derivatives 1 6 7 3 9 12 Other commodity derivatives — 1 1 — 2 2 Currency commercial derivatives 9 17 26 4 14 18 Other financial liabilities - derivatives 11 30 41 8 34 42 16.3 Valuation hierarchy The following table provides an analysis of financial instruments measured at fair value, grouped into levels based on the degree to which the fair value is observable: • Level 1 is based on a quoted price (unadjusted) in active markets for identical financial instruments. Level 1 includes aluminium, copper and zinc futures that are traded on the LME. • Level 2 is based on inputs other than quoted prices included within Level 1 that are observable for the assets or liabilities, either directly (i.e. prices) or indirectly (i.e. derived from prices). Level 2 includes foreign exchange derivatives, natural gas derivatives, silver derivatives and premium derivatives. The present value of future cash flows based on the forward or on the spot exchange rates at the balance sheet date is used to value foreign exchange derivatives. • Level 3 is based on inputs for the asset or liability that are not based on observable market data (unobservable inputs). Trade receivables are classified as a Level 3 measurement under the fair value hierarchy. At June 30, At December 31, (in millions of Euros) Level 1 Level 2 Level 3 Total Level 1 Level 2 Level 3 Total Other financial assets - derivatives 15 9 — 24 17 15 — 32 Other financial liabilities - derivatives 6 35 — 41 7 35 — 42 There was no material transfer of asset and liability categories into or out of Level 1, Level 2 or Level 3 during the six months ended June 30, 2024 nor the year ended December 31, 2023.

FINANCIAL RISK MANAGEMENT

FINANCIAL RISK MANAGEMENT	6 Months Ended
	Jun. 30, 2024
Disclosure of financial risk management [Abstract]
FINANCIAL RISK MANAGEMENT	NOTE 17 - FINANCIAL RISK MANAGEMENT The Group’s financial risk management strategy focuses on minimizing the cash flow impacts of volatility in foreign currency exchange rates and metal prices, while maintaining the financial flexibility the Group requires in order to successfully execute its business strategy. Due to Constellium’s capital structure and the nature of its operations, the Group is exposed to the following financial risks: (i) market risk including foreign exchange, commodity price and interest rate risks; (ii) credit risk and (iii) liquidity risk. 17.1 Market risk i. Commercial transaction exposures The Group has agreed to supply a major customer with fabricated metal products from a Euro functional currency entity and invoices in U.S. Dollars. The Group has entered into significant foreign exchange derivatives that matched related highly probable future conversion sales. The Group designates these derivatives for hedge accounting, with a total nominal amount of $470 million a nd $209 million at June 30, 2024 and December 31, 2023 respectively, with maturities ranging from 2024 to 2029. The table below details the effect of foreign currency derivatives in the Interim Income Statement and the Interim Statement of Comprehensive Income: Three months ended June 30, Six months ended June 30, (in millions of Euros) Notes 2024 2023 2024 2023 Derivatives that do not qualify for hedge accounting Included in Other gains and losses - net Realized (losses) / gains on foreign currency derivatives - net 6 (2) 5 (4) 9 Unrealized losses on foreign currency derivatives - net (A) 6 (3) (6) (11) (4) Derivatives that qualify for hedge accounting Included in Other comprehensive income Unrealized (losses) / gains on foreign currency derivatives - net (5) — (9) 2 Gains reclassified from cash flow hedge reserve to the Consolidated Income Statement 3 1 5 2 Included in Revenue (B) Realized losses on foreign currency derivatives - net 6 (2) (1) (4) (3) Unrealized (losses) / gains on foreign currency derivatives - net 6 — — (1) 1 (A) Gains or losses on the hedging instruments are expected to offset losses or gains on the underlying hedged forecasted sales that will be reflected in the future when these sales are recognized. (B) Changes in fair value of derivatives that qualify for hedge accounting are included in Revenue when the related customer invoices are issued. ii. Commodities The Group does not apply hedge accounting on commodity derivatives and therefore any mark-to-market movements are recognized in Other gains and losses – net. 17.2 Liquidity risk management The liquidity requirements of the overall Company are funded by cash and drawings on available credit facilities, while the internal management of liquidity is optimized by means of cash pooling agreements and/or intercompany loans and deposit between the Company’s operating entities and central Treasury. At June 30, 2024, the borrowing bases for the Pan-U.S. ABL and the French Inventory F acility were €467 million and €100 million, respectively. After deduction of amounts drawn and letters of credit, the Group had €552 million outstanding availability under these revolving credit facilities. At June 30, 2024, liquidity w as €869 million, comp rised of €213 million of cash and cash equivalents and €656 million o f available undrawn facilities, including the €552 million described above. Margin calls The Group's financial institution counterparties may require margin calls should the mark-to-market of our derivatives hedging foreign exchange and commodity price risks exceed a pre-agreed contractual limit. In order to protect from potential margin calls for significant market movements, the Group enters into derivatives with a large number of financial counterparties and monitors margin requirements on a daily basis. In addition, the Group (i) tries to offset exposures with financial counterparts and (ii) holds a significant liquidity buffer in cash or in availability under its various borrowing facilities. At June 30, 2024, and December 31, 2023 , there was no margin requirement paid as collateral to counterparties related to foreign exchange hedges nor related to aluminium or any other commodity hedges.

PENSIONS AND OTHER POST-EMPLOYM

PENSIONS AND OTHER POST-EMPLOYMENT BENEFIT OBLIGATIONS	6 Months Ended
	Jun. 30, 2024
Disclosure of employee benefits [Abstract]
PENSION AND OTHER POST-EMPLOYMENT BENEFIT OBLIGATIONS	NOTE 18 - PENSION AND OTHER POST-EMPLOYMENT BENEFIT OBLIGATIONS 18.1 Actuarial assumptions Pension and other post-employment benefit obligations were updated based on the discount rates applicable at June 30, 2024. At June 30, At December 31, Discount rate Discount rate Switzerland 1.45% 1.40% U.S. Hourly pension 5.30% - 5.35% 4.85% - 4.90% Salaried pension 5.35% 4.85% OPEB 5.30% - 5.40% 4.85% - 4.90% Other benefits 5.25% - 5.30% 4.75% - 4.85% France Retirements 3.65% 3.30% Other benefits 3.60% 3.25% Germany 3.65% 3.30% 18.2 Amounts recognized in the Interim Statement of Financial Position At June 30, At December 31, (in millions of Euros) Pension Benefits Other Benefits Total Pension Benefits Other Benefits Total Present value of funded obligation 629 — 629 653 — 653 Fair value of plan assets (492) — (492) (488) — (488) Deficit of funded plans 137 — 137 165 — 165 Present value of unfunded obligation 104 139 243 103 143 246 Net liability / (asset) arising from defined benefit obligation 241 139 380 268 143 411 18.3 Amounts recognized in the Interim Income Statement Three months ended June 30, 2024 2023 (in millions of Euros) Pension Benefits Other Benefits Total Pension Benefits Other Benefits Total Service cost Current service cost (4) (1) (5) (3) (2) (5) Net interest (3) (2) (5) (3) (1) (4) Immediate recognition of gains arising over the year — 1 1 — — — Administration expenses — — — — — — Total (7) (2) (9) (6) (3) (9) Six months ended June 30, 2024 2023 (in millions of Euros) Pension Benefits Other Benefits Total Pension Benefits Other Benefits Total Service cost Current service cost (8) (2) (10) (7) (3) (10) Net interest (4) (4) (8) (5) (3) (8) Immediate recognition of gains arising over the year — 1 1 — — — Administration expenses (1) — (1) (1) — (1) Total (13) (5) (18) (13) (6) (19) 18.4 Movement in net defined benefit obligations Six months ended June 30, 2024 Defined benefit obligations Plan Assets Net defined benefit liability (in millions of Euros) Pension benefits Other benefits Total At January 1, 2024 756 143 899 (488) 411 Included in the Consolidated Income Statement Current service cost 8 2 10 — 10 Interest cost / (income) 11 4 15 (7) 8 Immediate recognition of losses arising over the year — (1) (1) — (1) Administration expenses — — — 1 1 Included in the Statement of Comprehensive Income Remeasurements due to: —actual return less interest on plan assets — — — (9) (9) —changes in financial assumptions (21) (5) (26) — (26) —changes in demographic assumptions — — — — — —experience losses 1 1 2 — 2 Effects of changes in foreign exchange rates (2) 3 1 3 4 Included in the Consolidated Statement of Cash Flows Benefits paid (22) (8) (30) 19 (11) Contributions by the Group — — — (9) (9) Contributions by the plan participants 2 — 2 (2) — At June 30, 2024 733 139 872 (492) 380 18.5 Net defined benefit obligations by country At June 30, At December 31, (in millions of Euros) Defined benefit obligations Plan assets Net defined benefit liability Defined benefit obligations Plan assets Net defined benefit liability France 126 (6) 120 127 (6) 121 Germany 97 (1) 96 103 (1) 102 Switzerland 277 (267) 10 290 (265) 25 United States 372 (218) 154 379 (216) 163 Total 872 (492) 380 899 (488) 411

PROVISIONS

PROVISIONS	6 Months Ended
	Jun. 30, 2024
Disclosure of other provisions [abstract]
PROVISIONS	NOTE 19 - PROVISIONS (in millions of Euros) Close down and environmental remediation costs Restructuring Legal claims Total At January 1, 2024 86 — 21 107 Allowance — 1 — 1 Amounts used (1) — — (1) Unused amounts reversed — — (2) (2) Effects of changes in foreign exchange rates — — — — At June 30, 2024 85 1 19 105 Of which non-current 75 — 11 86 Of which current 10 1 8 19 Total provisions 85 1 19 105 Legal claims and other costs (in millions of Euros) At June 30, At December 31, Litigation 11 13 Disease claims 8 8 Total provisions for legal claims and other costs 19 21 Contingencies The Group is involved, and may become involved, in various lawsuits, claims and proceedings relating to customer claims, product liability, employee and retiree benefit matters and other commercial matters. The Group records provisions for pending litigation matters when it determines that it is probable that an outflow of resources will be required to settle the obligation, and such amounts can be reasonably estimated. In some proceedings, the issues raised can be highly complex and subject to significant uncertainties and amounts claimed can be substantial. As a result, the probability of loss and an estimation of damages can be difficult to ascertain. In exceptional cases, when the Group considers that disclosures relating to provisions and contingencies may prejudice its position, disclosures are limited to the general nature of the matter in hand.

NON-CASH INVESTING AND FINANCIN

NON-CASH INVESTING AND FINANCING TRANSACTIONS	6 Months Ended
	Jun. 30, 2024
Disclosure of cash flow statement [Abstract]
NON-CASH INVESTING AND FINANCING TRANSACTIONS	NOTE 20 - NON-CASH INVESTING AND FINANCING TRANSACTIONS Property, plant and equipment acquired through leases or financed by third parties amounted to €9 million and €7 million for the six months ended June 30, 2024 and 2023, respectively. These leases and financings are excluded from the Interim Statement of Cash Flows as they are non-cash investing transactions. Fair values of vested Restricted Stock Units and Performance Stock Units amounted to €19 million and €10 million for the six months ended June 30, 2024 and 2023, respectively. They are excluded from the Interim Statement of Cash Flows as non-cash financing activities.

SHARE CAPITAL

SHARE CAPITAL	6 Months Ended
	Jun. 30, 2024
Disclosure of share capital, reserves and other equity interest [Abstract]
SHARE CAPITAL	NOTE 21 - SHARE CAPITAL Share capital amounted to €2,936,397.68 at June 30, 2024, divided into 146,819,884 ordinary shares, each with a nominal value of two cents and fully paid-up. All shares are of the same class and except for treasury shares have the right to one vote. (in millions of Euros) Number of shares Share capital Share premium At January 1, 2024 146,819,884 3 420 At June 30, 2024 (A) 146,819,884 3 420 (A)

SHARE-BASED COMPENSATION

SHARE-BASED COMPENSATION	6 Months Ended
	Jun. 30, 2024
Share-based payment arrangements [Abstract]
SHARE-BASED COMPENSATION	NOTE 22 - SHARE-BASED COMPENSATION Description of plans Performance-Based Restricted Stock Units (equity-settled) In March 2024, the Company granted Performance Stock Units (PSUs) to selected employees and the CEO. These units vest if the following conditions are met: • A vesting condition under which the beneficiaries must be continuously at the service of the Company through the end of a three-year vesting period; and • A performance condition, contingent on the TSR performance of Constellium shares over the vesting period compared to the TSR of specified indices. PSUs will ultimately vest based on a vesting multiplier which ranges from 0% to 200%. The following table lists the inputs to the valuation model used for the PSUs granted in March 2024: March 2024 PSUs Fair value at grant date (in euros) 24.84 Share price at grant date (in euros) 18.14 Dividend yield — Expected volatility (A) 44% Risk-free interest rate (US government bond yield) 4.46% Model used Monte Carlo (A) Volatility in the share prices of the Company and companies included in indices were estimated based on observed historical volatilities over a period equal to the PSU vesting period. Restricted Stock Units Award Agreements (equity-settled) In March 2024, the Company granted Restricted Stock Units (RSUs) to selected employees and the CEO subject to the beneficiaries remaining continuously at the service of the Group from the grant date to the end of the three-year vesting period.The fair value of the RSUs awarded is €18.14, being the euro equivalent of the quoted market price at grant date. Expense recognized during the period In accordance with IFRS 2, share-based compensation is recognized as an expense over the vesting period. The estimate of this expense is based upon the fair value of a potential ordinary share at the grant date. The total share-based compensation amounted to €12 million and €10 million for the six months ended June 30, 2024 and 2023, respectively. Movement of potential shares PSUs RSUs Total potential shares At December 31, 2023 1,797,179 1,664,370 3,461,549 Granted (A) 600,268 545,477 1,145,745 Over-performance (B) 297,335 — 297,335 Vested (C) (864,792) (473,952) (1,338,744) Forfeited (D) (12,184) (16,344) (28,528) At June 30, 2024 1,817,806 1,719,551 3,537,357 (A) For PSUs, the number of potential shares granted is presented using a vesting multiplier of 100%. (B) When the achievement of TSR performance exceeds the vesting multiplier of 100%, the additional potential shares are presented as over-performance shares. (C) During the six months ended June 30, 2024, Constellium SE delivered 1,338,744 ordinary shares previously repurchased by Constellium SE to beneficiaries of a share-based compensation plan vested in May 2024. (D) For potential shares related to PSUs, 12,184 were forfeited as a result of the departure of certain beneficiaries and none were forfeited in relation to the non-fulfilment of performance conditions.

SUBSEQUENT EVENTS

SUBSEQUENT EVENTS	6 Months Ended
	Jun. 30, 2024
Disclosure of non-adjusting events after reporting period [abstract]
SUBSEQUENT EVENTS	NOTE 23 - SUBSEQUENT EVENTS

SUMMARY OF SIGNIFICANT ACCOUN_2

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Policies)	6 Months Ended
	Jun. 30, 2024
Disclosure of summary of significant accounting policies [abstract]
Basis of preparation	Basis of preparation The Unaudited Interim Condensed Consolidated Financial Statements (the "Interim Financial Statements") have been prepared in accordance with IAS 34 - Interim Financial Reporting . Accordingly, they do not include all the information and disclosures required in consolidated financial statements and should be read in conjunction with the Group’s Consolidated Financial Statements for the year ended December 31, 2023. In accordance with IAS 1- Presentation of Financial Statements , the Interim Financial Statements are prepared on the assumption that Constellium is a going concern and will continue in operation for the foreseeable future. The accounting policies adopted in the preparation of the Interim Financial Statements are consistent with those followed in the preparation of the Group’s Consolidated Financial Statements for the year ended December 31, 2023, except for the application of the effective tax rate method in accordance with IAS 34 - Interim Financial Reporting . The Interim Financial Statements are presented in millions of Euros, except when otherwise indicated. Certain reclassifications may have been made to prior year amounts to conform to the current year presentation. Amounts may not sum due to rounding. The Interim Financial Statements were authorized for issue by management on July 22, 2024.
New and amended standards and interpretations	New and amended standards and interpretations Several amendments to IFRS standards apply for the first time in 2024, but have no impact on the Interim Financial Statements of the Group. The Group has applied the mandatory exception to recognizing and disclosing information about deferred tax assets and liabilities arising from Pillar Two income taxes. The Group has reviewed its corporate structure in light of the introduction of Pillar Two Model Rules in the jurisdictions where it operates based on the most recent tax filings and financial statements. Based on this assessment, the Group has determined that it is not subject to Pillar Two “top-up” taxes for the the six months ended June 30, 2024. The Group has not early adopted any standard, interpretation or amendment that has been issued but is not yet effective. The Group plans to adopt new standards and interpretations on their required effective dates.
Judgments in applying accounting policies and key sources of estimation uncertainty	2.3 Judgments in applying accounting policies and key sources of estimation uncertainty The preparation of financial statements requires management to make judgements, estimates and assumptions that affect the reported amounts of revenues, expenses, assets and liabilities, along with the accompanying disclosures and the disclosure of contingent liabilities. These judgments, estimates and assumptions are based on management’s best knowledge of the relevant facts and circumstances, giving consideration to previous experience. However, actual results may differ from the amounts included in the financial statements. In preparing these Interim Financial Statements, the significant judgments made by management in applying the Group’s accounting policies and the key sources of estimation uncertainty were the same as those applied to the Consolidated Financial Statements at and for the year ended December 31, 2023, as well as the application of the effective tax rate method for the determination of the income tax provision.

SUMMARY OF SIGNIFICANT ACCOUN_3

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Tables)	6 Months Ended
	Jun. 30, 2024
Disclosure of summary of significant accounting policies [abstract]
Schedule of Main Exchange Rates Used for Preparation of Financial Statements	The following table summarizes the main exchange rates used for the preparation of the Interim Financial Statements: Average rates Closing rates Foreign exchange rate for 1 Euro Six months ended June 30, At June 30, At December 31, 2024 2023 2024 2023 U.S. Dollars USD 1.0812 1.0805 1.0705 1.1050 Swiss Francs CHF 0.9612 0.9855 0.9634 0.9260 Czech Koruna CZK 25.0118 23.6858 25.0250 24.7240

REVENUE (Tables)

REVENUE (Tables)	6 Months Ended
	Jun. 30, 2024
Revenue [abstract]
Schedule of Disaggregation Revenue	Three months ended June 30, Six months ended June 30, (in millions of Euros) 2024 2023 2024 2023 Packaging rolled products 677 699 1,295 1,384 Automotive rolled products 296 312 583 616 Specialty and other thin-rolled products 26 34 55 70 Aerospace rolled products 244 271 507 524 Transportation, industry, defense and other rolled products 195 190 363 385 Automotive extruded products 233 251 475 511 Other extruded products 123 193 245 416 Other metal sales 2 — 3 — Total Revenue by product line 1,795 1,950 3,526 3,906 Three months ended June 30, Six months ended June 30, (in millions of Euros) 2024 2023 2024 2023 Germany 372 447 734 926 France 163 178 337 360 United Kingdom 74 67 133 128 Switzerland 20 15 36 40 Spain 80 85 171 166 Czech Republic 52 67 106 124 Other Europe 247 241 474 483 Total Europe 1,008 1,100 1,991 2,227 United States 597 716 1,185 1,389 Asia and Other Pacific 70 61 138 122 All Other 120 73 212 168 Total Revenue by destination of shipment 1,795 1,950 3,526 3,906

OPERATING SEGMENT INFORMATION (

OPERATING SEGMENT INFORMATION (Tables)	6 Months Ended
	Jun. 30, 2024
Disclosure of operating segments [abstract]
Schedule of Segment Revenue	Three months ended June 30, Six months ended June 30, 2024 2023 2024 2023 (in millions of Euros) Segment revenue Inter-segment elimination External revenue Segment revenue Inter-segment elimination External revenue Segment revenue Inter-segment elimination External revenue Segment revenue Inter-segment elimination External revenue P&ARP 1,001 (2) 999 1,049 (4) 1,045 1,939 (6) 1,933 2,079 (9) 2,070 A&T 452 (13) 439 464 (2) 462 893 (23) 870 916 (7) 909 AS&I 357 (1) 356 443 — 443 721 (1) 720 926 — 926 H&C 2 — 2 — — — 3 — 3 1 — 1 Segment revenue 1,812 (17) 1,795 1,956 (6) 1,950 3,556 (30) 3,526 3,922 (16) 3,906
Schedule of Segment Adjusted EBITDA and reconciliation of Adjusted EBITDA to Net Income	Three months ended June 30, Six months ended June 30, (in millions of Euros) Notes 2024 2023 2024 2023 P&ARP 64 79 107 134 A&T 83 96 163 169 AS&I 32 39 65 82 H&C (7) (5) (13) (11) Segment Adjusted EBITDA 172 209 322 374 Metal price lag (A) 42 (30) 29 (45) Share based compensation costs 22 (6) (7) (12) (10) Depreciation and amortization 12, 13 (74) (72) (145) (144) Restructuring costs (B) 5 (3) — (3) — Unrealized gains / (losses) on derivatives 3 (20) — (28) Unrealized exchange (losses) / gains from the remeasurement of monetary assets and liabilities – net 5 — (1) 2 — Losses on disposal (C) 5 — — (1) (6) Other (D) (7) — (7) — Income from operations 127 79 185 141 Finance costs - net 7 (32) (35) (65) (70) Income before tax 95 44 120 71 Income tax expense 8 (24) (12) (32) (17) Net income 71 32 88 54 (A) Metal price lag represents the financial impact of the timing difference between when aluminium prices included within Constellium's Revenue are established and when aluminium purchase prices included in Cost of sales are established. The metal price lag will generally increase our earnings in times of rising primary aluminium prices and decrease our earnings in times of declining primary aluminium prices. The calculation of metal price lag adjustment is based on a standardized methodology applied at each of Constellium’s manufacturing sites. Metal price lag is calculated as the average value of product purchased in the period, approximated at the market price, less the value of product in inventory at the weighted average of metal purchased over time, multiplied by the quantity sold in the period. (B) For the six months ended June 30, 2024, restructuring costs amounted to €3 million and were related to cost improvement programs in Europe and in the U.S. (C) For the six months ended June 30, 2023, gains and losses on disposal costs net of transaction costs included a €5 million loss related to the sale of Constellium Ussel S.A.S. completed on February 2, 2023. (D) For the six months ended June 30, 2024, other was related to €5 million of inventory impairment as a result of flooding in Sierre and Chippis facilities at the end of June 2024 (refer to NOTE 23 - SUBSEQUENT EVENTS) as well as €2 million of costs associated with non-recurring corporate transformation projects.
Schedule of Segment Capital Expenditures	Six months ended June 30, (in millions of Euros) 2024 2023 P&ARP (74) (71) A&T (38) (37) AS&I (32) (25) H&C (2) (1) Capital expenditures (146) (134)
Schedule of Segment Assets	(in millions of Euros) At June 30, At December 31, P&ARP 2,181 2,102 A&T 1,220 1,087 AS&I 690 673 H&C 377 313 Segment assets 4,468 4,175 Deferred income tax assets 234 252 Cash and cash equivalents 213 202 Other financial assets 24 32 Total Assets 4,939 4,661

OTHER GAINS AND LOSSES_NET (Tab

OTHER GAINS AND LOSSES—NET (Tables)	6 Months Ended
	Jun. 30, 2024
Analysis of income and expense [abstract]
Schedule of Other Gains and Losses—Net	Three months ended June 30, Six months ended June 30, (in millions of Euros) 2024 2023 2024 2023 Realized gains / (losses) on derivatives (A) 23 (19) 12 (23) Unrealized gains / (losses) on derivatives at fair value through profit and loss - net (A) 3 (20) — (28) Unrealized exchange (losses) / gains from the remeasurement of monetary assets and liabilities – net — (1) 2 — Restructuring costs (B) (3) — (3) — Losses on disposal (C) — — (1) (6) Other 1 (1) 1 1 Total other gains and losses - net 24 (41) 11 (56) (A) Realized and unrealized gains and losses are related to derivatives entered into with the purpose of mitigating exposure to volatility in foreign currencies and commodity prices, and that do not qualify for hedge accounting. (B) For the six months ended June 30, 2024, restructuring costs amounted to €3 million and related to cost improvement programs in Europe and in the U.S. (C)

CURRENCY GAINS _ (LOSSES) (Tabl

CURRENCY GAINS / (LOSSES) (Tables)	6 Months Ended
	Jun. 30, 2024
Analysis of income and expense [abstract]
Schedule of Currency Gains and Losses Included in Income from Operations	Three months ended June 30, Six months ended June 30, (in millions of Euros) Notes 2024 2023 2024 2023 Included in Revenue 17 (2) (1) (5) (2) Included in Cost of sales — — — (1) Included in Other gains and losses - net (5) (1) (13) 5 Total (7) (2) (18) 2 Realized exchange (losses) / gains on foreign currency derivatives - net 17 (4) 4 (8) 6 Unrealized losses on foreign currency derivatives - net 17 (3) (6) (12) (3) Exchange gains / (losses) from the remeasurement of monetary assets and liabilities - net — — 2 (1) Total (7) (2) (18) 2

FINANCE COSTS_NET (Tables)

FINANCE COSTS—NET (Tables)	6 Months Ended
	Jun. 30, 2024
Analysis of income and expense [abstract]
Schedule of Finance Costs—Net	Three months ended June 30, Six months ended June 30, (in millions of Euros) 2024 2023 2024 2023 Interest expense on borrowings (A) (21) (25) (44) (49) Interest expense on leases (2) (2) (4) (5) Interest cost on pension and other benefits (5) (4) (8) (8) Expenses on factoring arrangements (5) (5) (9) (10) Realized and unrealized gains / (losses) on debt derivatives at fair value (B) — 4 (1) 4 Realized and unrealized exchange gains / (losses) on financing activities - net (B) 1 (3) 1 (2) Other finance expenses (1) (1) (2) (2) Capitalized borrowing costs (C) 1 1 2 2 Finance expenses (32) (35) (65) (70) Finance costs - net (32) (35) (65) (70) (A) For the six months ended June 30, 2024 and 2023 , interest expense on borrowings inc luded €38 million of interest, and €2 million of am ortization of arrangement fees related to Constellium SE Senior Notes. (B) The Group hedges the dollar exposure, relating to the principal of its Constellium SE U.S. Dollar Senior Notes, for the portion that has not been used to finance directly or indirectly U.S. Dollar functional currency entities. Changes in the fair value of these hedging derivatives are recognized within Finance costs – net in the Interim Income Statement. (C) Borrowing costs directly attributable to the construction of assets are capitalized. The capitalization rate w as 5% for the six months ended June 30, 2024 and 2023.

TRADE RECEIVABLES AND OTHER (Ta

TRADE RECEIVABLES AND OTHER (Tables)	6 Months Ended
	Jun. 30, 2024
Trade and other receivables [abstract]
Schedule of Trade Receivables and Other	NOTE 10 - TRADE RECEIVABLES AND OTHER At June 30, At December 31, (in millions of Euros) Non-current Current Non-current Current Trade receivables - gross — 580 — 388 Impairment — (2) — (2) Total trade receivables - net — 578 — 386 Income tax receivables 4 26 — 17 Other tax receivables — 43 — 54 Contract assets 17 2 16 2 Prepaid expenses — 21 — 8 Other 14 23 15 23 Total other receivables 35 115 31 104 Total trade receivables and other 35 693 31 490 10.1 Contract assets Contracts assets includes €9 million at June 30, 2024 and €7 million at December 31, 2023 of unbilled tooling costs. 10.2 Aging (in millions of Euros) At June 30, At December 31, Not past due 560 370 1 – 30 days past due 16 15 31 – 60 days past due 1 1 61 – 90 days past due 1 — Total trade receivables - net 578 386 The maximum exposure to credit risk at the reporting date is the carrying value of each class of receivable shown above. The Group does not hold any collateral from its customers or debtors as security. 10.3 Currency concentration (in millions of Euros) At June 30, At December 31, Euro 289 167 U.S. Dollar 270 200 Swiss franc 7 7 Other currencies 12 12 Total trade receivables - net 578 386 10.4 Factoring arrangements The Group factors trade receivables under committed factoring agreements in the United States, France, Germany, Switzerland and the Czech Republic: • In the United States, Constellium Muscle Shoals LLC is party to a factoring agreement with a capacity of $175 million and a maturity date in September 2025 and Constellium Automotive USA LLC is party to a factoring agreement with a maximum capacity of $25 million and a maturity date in December 2024. • The factoring agreement in place for our entities in France has a maximum capacity of €250 million (including a €20 million recourse line) and a maturity date in January 2026. • Factoring agreements in place for our entities in Germany, Switzerland and the Czech Republic have a combined maximum capacity of €200 million and maturity dates in December 2027. In addition, the Group sells receivables from one of its German customers under an uncommitted factoring facility whereby receivables sold are confirmed by the customer. These factoring agreements contain certain customary affirmative and negative covenants, including some relating to the administration and collection of the assigned receivables, the terms of the invoices and the exchange of information, but do not contain maintenance financial covenants. In addition, the com mitment of the factor to buy receivables under the Muscle Shoals factoring agreement is subject to certain credit ratings being maintained. The Group was in compliance with all applicable covenants at and for the six months ended June 30, 2024 and 2023. Under the Group’s factoring agreements, most of the trade receivables, when sold, are sold without recourse. Where the Group has transferred substantially all the risks and rewards of ownership of the receivables, the receivables are derecognized. Some remaining receivables do not qualify for derecognition , as the Group retains substantially all the associated risks and rewards. At June 30, 2024, the total carrying amount of the original assets factored was €580 million, of which €360 million had been derecognized. At December 31, 2023, the total carrying amount of the original assets factored was €494 million, of which €356 million had been derecognized. Amounts due to the factors in respect of trade receivable s sold were €1 million a nd €1 million at June 30, 2024 and December 31, 2023, respectively.
Schedule of Aging of Total Trade Receivables—Net	(in millions of Euros) At June 30, At December 31, Not past due 560 370 1 – 30 days past due 16 15 31 – 60 days past due 1 1 61 – 90 days past due 1 — Total trade receivables - net 578 386
Schedule of Carrying Amounts of Total Trade Receivables—Net by Currency	(in millions of Euros) At June 30, At December 31, Euro 289 167 U.S. Dollar 270 200 Swiss franc 7 7 Other currencies 12 12 Total trade receivables - net 578 386

INVENTORIES (Tables)

INVENTORIES (Tables)	6 Months Ended
	Jun. 30, 2024
Subclassifications of assets, liabilities and equities [abstract]
Schedule of Inventories	(in millions of Euros) At June 30, At December 31, Finished goods 234 260 Work in progress 625 537 Raw materials 203 231 Stores and supplies 128 123 Inventories write down (56) (53) Total inventories 1,134 1,098

PROPERTY, PLANT AND EQUIPMENT (

PROPERTY, PLANT AND EQUIPMENT (Tables)	6 Months Ended
	Jun. 30, 2024
Property, plant and equipment [abstract]
Schedule of Property, Plant and Equipment	(in millions of Euros) Land and Property Rights Buildings Machinery and Equipment Construction Work in Progress Other Total Net balance at January 1, 2024 25 379 1,381 251 11 2,047 Additions 1 3 36 114 2 156 Disposals — — (2) — — (2) Depreciation expense (1) (17) (119) — (4) (141) Transfer and other changes 1 4 38 (46) 2 (1) Effect of changes in foreign exchange rates — 3 20 2 — 25 Net balance at June 30, 2024 26 372 1,354 321 11 2,084 Cost 47 672 3,198 333 55 4,305 Less accumulated depreciation and impairment (21) (300) (1,844) (12) (44) (2,221) Net balance at June 30, 2024 26 372 1,354 321 11 2,084
Schedule of Right of Use Assets	Right-of-use assets have been included in the same line item as that in which a corresponding owned asset would be presented. (in millions of Euros) Buildings Machinery and Equipment Other Total Net balance at January 1, 2024 103 38 — 141 Additions 3 8 — 11 Depreciation expense (6) (6) — (12) Net balance at June 30, 2024 100 40 — 140 Cost 172 107 — 279 Less accumulated depreciation and impairment (72) (67) — (139) Net balance at June 30, 2024 100 40 — 140

INTANGIBLE ASSETS AND GOODWILL

INTANGIBLE ASSETS AND GOODWILL (Tables)	6 Months Ended
	Jun. 30, 2024
Intangible assets and goodwill [abstract]
Schedule of Changes in Intangible Assets and Goodwill	(in millions of Euros) Technology Computer Software Customer relationships Work in Progress Other Total Intangible Assets Goodwill Net balance at January 1, 2024 16 13 12 3 3 47 462 Additions — — — 1 — 1 — Amortization expense (1) (2) — (1) — (4) — Effect of changes in foreign exchange rates 1 — — — — 1 15 Net balance at June 30, 2024 16 11 12 3 3 45 477 Cost 92 88 42 4 4 230 477 Less accumulated depreciation and impairment (76) (77) (30) (1) (1) (185) — Net balance at June 30, 2024 16 11 12 3 3 45 477

TRADE PAYABLES AND OTHER (Table

TRADE PAYABLES AND OTHER (Tables)	6 Months Ended
	Jun. 30, 2024
Trade and other payables [abstract]
Schedule of Trade Payables and Other	At June 30, At December 31, (in millions of Euros) Non-current Current Non-current Current Trade payables — 1,099 — 931 Fixed assets payables — 41 — 35 Employees' entitlements — 195 — 211 Taxes payable other than income tax — 32 — 15 Contract liabilities and other liabilities to customers 31 54 29 62 Other payables 37 10 30 9 Total other 68 332 59 332 Total trade payables and other 68 1,431 59 1,263
Schedule of Contract Liabilities	At June 30, At December 31, (in millions of Euros) Non-current Current Non-current Current Deferred tooling revenue 30 — 28 — Advance payment from customers — 12 — 7 Unrecognized variable consideration (A) 1 42 1 55 Total contract liabilities and other liabilities to customers 31 54 29 62 (A) Unrecognized variable consideration consists of expected volume rebates, discounts, incentives, refunds penalties and price concessions.

BORROWINGS (Tables)

BORROWINGS (Tables)	6 Months Ended
	Jun. 30, 2024
Borrowings [abstract]
Schedule of Borrowings by Nature	At June 30, At December 31, (in millions of Euros) Nominal Value in Currency Nominal rate Nominal Value in Euros (Arrange-ment fees) Accrued interests Carrying value Carrying Senior Unsecured Notes (A) Issued November 2017 and due 2026 $ 250 5.875% 234 (1) 5 238 230 Issued November 2017 and due 2026 € 400 4.250% 400 (2) 6 404 404 Issued June 2020 and due 2028 $ 325 5.625% 303 (3) 1 301 291 Issued February 2021 and due 2029 $ 500 3.750% 467 (5) 4 466 452 Issued June 2021 and due 2029 € 300 3.125% 300 (3) 4 301 300 Lease liabilities 151 — 1 152 154 Other loans (B) 33 — — 33 37 Total Borrowings 1,888 (14) 21 1,895 1,868 Of which non-current 1,842 1,814 Of which current 53 54 (A) The Senior Unsecured Notes were issued by Constellium SE and are guaranteed by certain subsidiaries. (B) Other loans inclu de €28 million o
Schedule of Movement in Borrowings	(in millions of Euros) At June 30, At December 31, At January 1, 1,868 2,056 Cash flows Repayments of long-term borrowings (A) (4) (53) Net change in revolving credit facilities and short-term borrowings (B) — (83) Lease repayments (13) (37) Non-cash changes Movement in accrued interest — (1) Changes in leases and other loans 9 24 Deferred arrangement fees 2 4 Effects of changes in foreign exchange rates 33 (42) At the end of the period 1,895 1,868 (A) For the twelve months ended December 31, 2023, repayments of long-term borrowings included the redemption of $50 million out of the $300 million outstanding aggregate principal amount of the 5.875% Senior Notes due 2026 on July 20, 2023. (B) For the twelve months ended December 31, 2023 , the net change in revolving credit facilities and short-term borrowings included mainly the repayment under the Pan-U.S. ABL.
Schedule of Currency Concentration of Total Borrowings	(in millions of Euros) At June 30, At December 31, 2023 U.S. Dollar 1,044 1,012 Euro 845 849 Other currencies 6 7 Total borrowings 1,895 1,868

FINANCIAL INSTRUMENTS (Tables)

FINANCIAL INSTRUMENTS (Tables)	6 Months Ended
	Jun. 30, 2024
Disclosure of detailed information about financial instruments [abstract]
Schedule of Financial Assets and Liabilities by Categories	At June 30, At December 31, (in millions of Euros) Notes At amortized cost At fair value through profit and loss At fair value through OCI Total At amortized cost At fair value through profit and loss At fair value through OCI Total Cash and cash equivalents 9 213 — — 213 202 — — 202 Trade receivables 10 — — 578 578 — — 386 386 Other financial assets — 24 — 24 — 31 1 32 Total 213 24 578 815 202 31 387 620 At June 30, At December 31, (in millions of Euros) Notes At amortized cost At fair value through profit and loss At fair value through OCI Total At amortized cost At fair value through profit and loss At fair value through OCI Total Trade payables and fixed asset payables 14 1,140 — — 1,140 966 — — 966 Borrowings 15 1,895 — — 1,895 1,868 — — 1,868 Other financial liabilities — 31 10 41 — 35 7 42 Total 3,035 31 10 3,076 2,834 35 7 2,876
Schedule of Other Financial Assets and Other Financial Liabilities Positions	At June 30, At December 31, (in millions of Euros) Non-current Current Total Non-current Current Total Aluminium and premium derivatives 2 15 17 1 17 18 Other commodity derivatives — 4 4 — 1 1 Currency commercial derivatives — 3 3 1 10 11 Currency net debt derivatives — — — — 2 2 Other financial assets - derivatives 2 22 24 2 30 32 Aluminium and premium derivatives 1 6 7 1 9 10 Energy derivatives 1 6 7 3 9 12 Other commodity derivatives — 1 1 — 2 2 Currency commercial derivatives 9 17 26 4 14 18 Other financial liabilities - derivatives 11 30 41 8 34 42
Schedule of Derivatives Measured at Fair Value	At June 30, At December 31, (in millions of Euros) Level 1 Level 2 Level 3 Total Level 1 Level 2 Level 3 Total Other financial assets - derivatives 15 9 — 24 17 15 — 32 Other financial liabilities - derivatives 6 35 — 41 7 35 — 42

FINANCIAL RISK MANAGEMENT (Tabl

FINANCIAL RISK MANAGEMENT (Tables)	6 Months Ended
	Jun. 30, 2024
Disclosure of detailed information about hedging instruments [table]
Schedule of Effect of Foreign Currency Derivatives Impacts in Consolidated Income Statement and Statement of Comprehensive Income/(Loss)	The table below details the effect of foreign currency derivatives in the Interim Income Statement and the Interim Statement of Comprehensive Income: Three months ended June 30, Six months ended June 30, (in millions of Euros) Notes 2024 2023 2024 2023 Derivatives that do not qualify for hedge accounting Included in Other gains and losses - net Realized (losses) / gains on foreign currency derivatives - net 6 (2) 5 (4) 9 Unrealized losses on foreign currency derivatives - net (A) 6 (3) (6) (11) (4) Derivatives that qualify for hedge accounting Included in Other comprehensive income Unrealized (losses) / gains on foreign currency derivatives - net (5) — (9) 2 Gains reclassified from cash flow hedge reserve to the Consolidated Income Statement 3 1 5 2 Included in Revenue (B) Realized losses on foreign currency derivatives - net 6 (2) (1) (4) (3) Unrealized (losses) / gains on foreign currency derivatives - net 6 — — (1) 1 (A) Gains or losses on the hedging instruments are expected to offset losses or gains on the underlying hedged forecasted sales that will be reflected in the future when these sales are recognized. (B) Changes in fair value of derivatives that qualify for hedge accounting are included in Revenue when the related customer invoices are issued.

PENSIONS AND OTHER POST-EMPLO_2

PENSIONS AND OTHER POST-EMPLOYMENT BENEFIT OBLIGATIONS (Tables)	6 Months Ended
	Jun. 30, 2024
Disclosure of employee benefits [Abstract]
Schedule of Sensitivity Analysis and Actuarial Assumptions	At June 30, At December 31, Discount rate Discount rate Switzerland 1.45% 1.40% U.S. Hourly pension 5.30% - 5.35% 4.85% - 4.90% Salaried pension 5.35% 4.85% OPEB 5.30% - 5.40% 4.85% - 4.90% Other benefits 5.25% - 5.30% 4.75% - 4.85% France Retirements 3.65% 3.30% Other benefits 3.60% 3.25% Germany 3.65% 3.30%
Schedule of Amounts Recognized in the Consolidated Statement of Financial Position	At June 30, At December 31, (in millions of Euros) Pension Benefits Other Benefits Total Pension Benefits Other Benefits Total Present value of funded obligation 629 — 629 653 — 653 Fair value of plan assets (492) — (492) (488) — (488) Deficit of funded plans 137 — 137 165 — 165 Present value of unfunded obligation 104 139 243 103 143 246 Net liability / (asset) arising from defined benefit obligation 241 139 380 268 143 411
Disclosure Of Defined Benefit Plans Expense Recognised In Income Statement Explanatory	Three months ended June 30, 2024 2023 (in millions of Euros) Pension Benefits Other Benefits Total Pension Benefits Other Benefits Total Service cost Current service cost (4) (1) (5) (3) (2) (5) Net interest (3) (2) (5) (3) (1) (4) Immediate recognition of gains arising over the year — 1 1 — — — Administration expenses — — — — — — Total (7) (2) (9) (6) (3) (9) Six months ended June 30, 2024 2023 (in millions of Euros) Pension Benefits Other Benefits Total Pension Benefits Other Benefits Total Service cost Current service cost (8) (2) (10) (7) (3) (10) Net interest (4) (4) (8) (5) (3) (8) Immediate recognition of gains arising over the year — 1 1 — — — Administration expenses (1) — (1) (1) — (1) Total (13) (5) (18) (13) (6) (19)
Schedule of Movement in Net Defined Benefit Obligations	Six months ended June 30, 2024 Defined benefit obligations Plan Assets Net defined benefit liability (in millions of Euros) Pension benefits Other benefits Total At January 1, 2024 756 143 899 (488) 411 Included in the Consolidated Income Statement Current service cost 8 2 10 — 10 Interest cost / (income) 11 4 15 (7) 8 Immediate recognition of losses arising over the year — (1) (1) — (1) Administration expenses — — — 1 1 Included in the Statement of Comprehensive Income Remeasurements due to: —actual return less interest on plan assets — — — (9) (9) —changes in financial assumptions (21) (5) (26) — (26) —changes in demographic assumptions — — — — — —experience losses 1 1 2 — 2 Effects of changes in foreign exchange rates (2) 3 1 3 4 Included in the Consolidated Statement of Cash Flows Benefits paid (22) (8) (30) 19 (11) Contributions by the Group — — — (9) (9) Contributions by the plan participants 2 — 2 (2) — At June 30, 2024 733 139 872 (492) 380
Schedule of Net Defined Benefit Obligations by Country	At June 30, At December 31, (in millions of Euros) Defined benefit obligations Plan assets Net defined benefit liability Defined benefit obligations Plan assets Net defined benefit liability France 126 (6) 120 127 (6) 121 Germany 97 (1) 96 103 (1) 102 Switzerland 277 (267) 10 290 (265) 25 United States 372 (218) 154 379 (216) 163 Total 872 (492) 380 899 (488) 411

PROVISIONS (Tables)

PROVISIONS (Tables)	6 Months Ended
	Jun. 30, 2024
Disclosure of other provisions [abstract]
Schedule of Changes in Provisions	(in millions of Euros) Close down and environmental remediation costs Restructuring Legal claims Total At January 1, 2024 86 — 21 107 Allowance — 1 — 1 Amounts used (1) — — (1) Unused amounts reversed — — (2) (2) Effects of changes in foreign exchange rates — — — — At June 30, 2024 85 1 19 105 Of which non-current 75 — 11 86 Of which current 10 1 8 19 Total provisions 85 1 19 105
Schedule of Legal Claims and Other Costs	(in millions of Euros) At June 30, At December 31, Litigation 11 13 Disease claims 8 8 Total provisions for legal claims and other costs 19 21

SHARE CAPITAL (Tables)

SHARE CAPITAL (Tables)	6 Months Ended
	Jun. 30, 2024
Disclosure of share capital, reserves and other equity interest [Abstract]
Schedule of Share Capital	(in millions of Euros) Number of shares Share capital Share premium At January 1, 2024 146,819,884 3 420 At June 30, 2024 (A) 146,819,884 3 420 (A)

SHARE-BASED COMPENSATION (Table

SHARE-BASED COMPENSATION (Tables)	6 Months Ended
	Jun. 30, 2024
Share-based payment arrangements [Abstract]
Schedule of Inputs to the Model Used for PSUs Granted	The following table lists the inputs to the valuation model used for the PSUs granted in March 2024: March 2024 PSUs Fair value at grant date (in euros) 24.84 Share price at grant date (in euros) 18.14 Dividend yield — Expected volatility (A) 44% Risk-free interest rate (US government bond yield) 4.46% Model used Monte Carlo (A) Volatility in the share prices of the Company and companies included in indices were estimated based on observed historical volatilities over a period equal to the PSU vesting period.

GENERAL INFORMATION (Details)

GENERAL INFORMATION (Details)	Jun. 30, 2024 employee center facility site
Disclosure of general information [abstract]
Number of production facilities | facility	25
Number of R&D centers | center	3
Number of administrative centers | site	3
Number of employees | employee	12,000

SUMMARY OF SIGNIFICANT ACCOUN_4

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Disclosure of Foreign Exchange Rates (Details)	6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Dec. 31, 2023
U.S. Dollars
Disclosure of foreign exchange rates [line items]
Average rates	1.0812	1.0805
Closing rates	1.0705		1.1050
Swiss Francs
Disclosure of foreign exchange rates [line items]
Average rates	0.9612	0.9855
Closing rates	0.9634		0.9260
Czech Koruna
Disclosure of foreign exchange rates [line items]
Average rates	25.0118	23.6858
Closing rates	25.0250		24.7240

SUMMARY OF SIGNIFICANT ACCOUN_5

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - OLD Additional Information (Details) - EUR (€) € in Millions	Jun. 30, 2024	Dec. 31, 2023
Summary of significant accounting policies [line items]
Lease liabilities	€ 152	€ 154

SUMMARY OF SIGNIFICANT ACCOUN_6

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Impact of Initial Application of IFRS 16 - Leases (Details) - EUR (€) € in Millions	Jun. 30, 2024	Dec. 31, 2023	Dec. 31, 2022
Disclosure of initial application of standards or interpretations [abstract]
Property, plant and equipment	€ 2,084	€ 2,047
Borrowings	€ (1,895)	€ (1,868)	€ (2,056)

REVENUE - Disaggregation of Rev

REVENUE - Disaggregation of Revenue by Product Line (Details) - EUR (€) € in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Disclosure of products and services [line items]
Total Revenue	€ 1,795	€ 1,950	€ 3,526	€ 3,906
Packaging rolled products
Disclosure of products and services [line items]
Total Revenue	677	699	1,295	1,384
Automotive rolled products
Disclosure of products and services [line items]
Total Revenue	296	312	583	616
Specialty and other thin-rolled products
Disclosure of products and services [line items]
Total Revenue	26	34	55	70
Aerospace rolled products
Disclosure of products and services [line items]
Total Revenue	244	271	507	524
Transportation, industry, defense and other rolled products
Disclosure of products and services [line items]
Total Revenue	195	190	363	385
Automotive extruded products
Disclosure of products and services [line items]
Total Revenue	233	251	475	511
Other extruded products
Disclosure of products and services [line items]
Total Revenue	123	193	245	416
Other metal sales
Disclosure of products and services [line items]
Total Revenue	€ 2	€ 0	€ 3	€ 0

REVENUE - Disaggregation of R_2

REVENUE - Disaggregation of Revenue by Destination of Shipment (Details) - EUR (€) € in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Disclosure of geographical areas [line items]
Total Revenue	€ 1,795	€ 1,950	€ 3,526	€ 3,906
Total Europe
Disclosure of geographical areas [line items]
Total Revenue	1,008	1,100	1,991	2,227
Germany
Disclosure of geographical areas [line items]
Total Revenue	372	447	734	926
France
Disclosure of geographical areas [line items]
Total Revenue	163	178	337	360
United Kingdom
Disclosure of geographical areas [line items]
Total Revenue	74	67	133	128
Switzerland
Disclosure of geographical areas [line items]
Total Revenue	20	15	36	40
Spain
Disclosure of geographical areas [line items]
Total Revenue	80	85	171	166
Czech Republic
Disclosure of geographical areas [line items]
Total Revenue	52	67	106	124
Other Europe
Disclosure of geographical areas [line items]
Total Revenue	247	241	474	483
United States
Disclosure of geographical areas [line items]
Total Revenue	597	716	1,185	1,389
Asia and Other Pacific
Disclosure of geographical areas [line items]
Total Revenue	70	61	138	122
All Other
Disclosure of geographical areas [line items]
Total Revenue	€ 120	€ 73	€ 212	€ 168

OPERATING SEGMENT INFORMATION -

OPERATING SEGMENT INFORMATION - Narrative (Details)	Jun. 30, 2024 segment
Disclosure of operating segments [abstract]
Number of reportable segments	3

OPERATING SEGMENT INFORMATION_2

OPERATING SEGMENT INFORMATION - Segment Revenue (Details) - EUR (€) € in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Disclosure of operating segments [line items]
Revenue	€ 1,795	€ 1,950	€ 3,526	€ 3,906
P&ARP
Disclosure of operating segments [line items]
Revenue	999	1,045	1,933	2,070
A&T
Disclosure of operating segments [line items]
Revenue	439	462	870	909
AS&I
Disclosure of operating segments [line items]
Revenue	356	443	720	926
H&C
Disclosure of operating segments [line items]
Revenue	2	0	3	1
Segment revenue
Disclosure of operating segments [line items]
Revenue	1,812	1,956	3,556	3,922
Segment revenue | P&ARP
Disclosure of operating segments [line items]
Revenue	1,001	1,049	1,939	2,079
Segment revenue | A&T
Disclosure of operating segments [line items]
Revenue	452	464	893	916
Segment revenue | AS&I
Disclosure of operating segments [line items]
Revenue	357	443	721	926
Segment revenue | H&C
Disclosure of operating segments [line items]
Revenue	2	0	3	1
Inter-segment elimination
Disclosure of operating segments [line items]
Revenue	(17)	(6)	(30)	(16)
Inter-segment elimination | P&ARP
Disclosure of operating segments [line items]
Revenue	(2)	(4)	(6)	(9)
Inter-segment elimination | A&T
Disclosure of operating segments [line items]
Revenue	(13)	(2)	(23)	(7)
Inter-segment elimination | AS&I
Disclosure of operating segments [line items]
Revenue	(1)	0	(1)	0
Inter-segment elimination | H&C
Disclosure of operating segments [line items]
Revenue	€ 0	€ 0	€ 0	€ 0

OPERATING SEGMENT INFORMATION_3

OPERATING SEGMENT INFORMATION - Segment Adjusted EBITDA and reconciliation of Adjusted EBITDA to Net Income (Details) - EUR (€) € in Millions	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023	Dec. 31, 2023
Disclosure of segment adjusted EBITDA and reconciliation of adjusted EBITDA to net income [line items]
Adjusted EBITDA	€ 172	€ 209	€ 322	€ 374
Metal price lag	42	(30)	29	(45)
Share based compensation costs	(6)	(7)	(12)	(10)
Depreciation and amortization	(74)	(72)	(145)	(144)
Restructuring costs (B)	(3)	0	(3)	0
Unrealized gains / (losses) on derivatives	3	(20)	0	(28)
Unrealized exchange (losses) / gains from the remeasurement of monetary assets and liabilities – net	0	(1)	2	0
Losses on disposal	0	0	(1)	(6)
Other Adjustments	(7)	0	(7)	0
Income from operations	127	79	185	141
Finance costs - net	(32)	(35)	(65)	(70)
Income before tax	95	44	120	71
Income tax expense	(24)	(12)	(32)	(17)
Net income	71	32	88	54	€ 129
Write-downs (reversals of write-downs) of inventories			5
Other related project costs			2
P&ARP
Disclosure of segment adjusted EBITDA and reconciliation of adjusted EBITDA to net income [line items]
Adjusted EBITDA	64	79	107	134
A&T
Disclosure of segment adjusted EBITDA and reconciliation of adjusted EBITDA to net income [line items]
Adjusted EBITDA	83	96	163	169
AS&I
Disclosure of segment adjusted EBITDA and reconciliation of adjusted EBITDA to net income [line items]
Adjusted EBITDA	32	39	65	82
H&C
Disclosure of segment adjusted EBITDA and reconciliation of adjusted EBITDA to net income [line items]
Adjusted EBITDA	€ (7)	€ (5)	€ (13)	€ (11)

OPERATING SEGMENT INFORMATION_4

OPERATING SEGMENT INFORMATION - Segment Capital Expenditures (Details) - EUR (€) € in Millions	6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023
Disclosure of operating segments [line items]
Capital expenditures	€ (146)	€ (134)
P&ARP
Disclosure of operating segments [line items]
Capital expenditures	(74)	(71)
A&T
Disclosure of operating segments [line items]
Capital expenditures	(38)	(37)
AS&I
Disclosure of operating segments [line items]
Capital expenditures	(32)	(25)
H&C
Disclosure of operating segments [line items]
Capital expenditures	€ (2)	€ (1)

OPERATING SEGMENT INFORMATION_5

OPERATING SEGMENT INFORMATION - Segment Assets (Details) - EUR (€) € in Millions	Jun. 30, 2024	Dec. 31, 2023	Jun. 30, 2023	Dec. 31, 2022
Disclosure of operating segments [line items]
Total Assets	€ 4,939	€ 4,661
Deferred tax assets	234	252
Cash and cash equivalents	213	202	€ 178	€ 166
Segment revenue
Disclosure of operating segments [line items]
Total Assets	4,468	4,175
Segment revenue | P&ARP
Disclosure of operating segments [line items]
Total Assets	2,181	2,102
Segment revenue | A&T
Disclosure of operating segments [line items]
Total Assets	1,220	1,087
Segment revenue | AS&I
Disclosure of operating segments [line items]
Total Assets	690	673
Segment revenue | H&C
Disclosure of operating segments [line items]
Total Assets	377	313
Unallocated
Disclosure of operating segments [line items]
Deferred tax assets	234	252
Cash and cash equivalents	213	202
Other financial assets	€ 24	€ 32

OTHER GAINS AND LOSSES_NET (Det

OTHER GAINS AND LOSSES—NET (Details) - EUR (€) € in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Disclosure of analysis of single amount of discontinued operations [line items]
Realized (losses) / gains on derivatives	€ 23	€ (19)	€ 12	€ (23)
Unrealized gains / (losses) on derivatives at fair value through profit and loss—net	3	(20)	0	(28)
Unrealized exchange (losses) / gains from the remeasurement of monetary assets and liabilities – net	0	(1)	2	0
Restructuring costs	(3)	0	(3)	0
Losses on disposal	0	0	(1)	(6)
Other	1	(1)	1	1
Total other gains and losses - net	€ 24	€ (41)	11	(56)
Proceeds from sale of subsidiary				€ 0.3
Disposal groups classified as held for sale
Disclosure of analysis of single amount of discontinued operations [line items]
Losses on disposal			€ 5

CURRENCY GAINS _ (LOSSES) - Cur

CURRENCY GAINS / (LOSSES) - Currency Gains and Losses Included in Income from Operations (Details) € in Millions, $ in Millions	3 Months Ended				6 Months Ended
	Jun. 30, 2024 EUR (€)	Jun. 30, 2024 USD ($)	Jun. 30, 2023 EUR (€)	Jun. 30, 2023 USD ($)	Jun. 30, 2024 EUR (€)	Jun. 30, 2024 USD ($)	Jun. 30, 2023 EUR (€)	Jun. 30, 2023 USD ($)
Analysis of income and expense [line items]
Total	€ (7)	$ (7)	€ (2)	$ (2)	€ (18)	$ (18)	€ 2	$ 2
Realized exchange (losses) / gains on foreign currency derivatives - net	(4)		4		(8)		6
Unrealized losses on foreign currency derivatives - net	(3)		(6)		(12)		(3)
Exchange gains / (losses) from the remeasurement of monetary assets and liabilities - net	0		0		2		(1)
Included in Revenue
Analysis of income and expense [line items]
Total	(2)		(1)		(5)		(2)
Included in Cost of sales
Analysis of income and expense [line items]
Total	0		0		0		(1)
Included in Other gains and losses - net
Analysis of income and expense [line items]
Total	€ (5)		€ (1)		€ (13)		€ 5

FINANCE COSTS_NET (Details)

FINANCE COSTS—NET (Details) - EUR (€) € in Millions	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023	Dec. 31, 2023
Analysis of income and expense [line items]
Interest expense on borrowings	€ (21)	€ (25)	€ (44)	€ (49)
Interest expense on leases	(2)	(2)	(4)	(5)
Interest cost on pension and other benefits	(5)	(4)	(8)	(8)
Expenses on factoring arrangements	(5)	(5)	(9)	(10)
Realized and unrealized (losses) / gains on debt derivatives at fair value	0	4	(1)	4
Realized and unrealized exchange (losses) / gains on financing activities - net	1	(3)	1	(2)
Other finance expenses	(1)	(1)	(2)	(2)
Capitalized borrowing costs	1	1	2	2
Finance expenses	(32)	(35)	(65)	(70)
Finance costs - net	€ (32)	€ (35)	(65)	(70)
Redemption of senior notes			€ 4	€ 5	€ 53
Capitalization rate			5%	5%
Constellium SE Senior Notes
Analysis of income and expense [line items]
Interest expense on borrowings				€ (38)
Borrowing costs recognised as expense			€ 2

CASH AND CASH EQUIVALENTS (Deta

CASH AND CASH EQUIVALENTS (Details) - EUR (€) € in Millions	Jun. 30, 2024	Dec. 31, 2023	Jun. 30, 2023	Dec. 31, 2022
Disclosure of cash and cash equivalents [line Items]
Cash in bank and on hand	€ 213	€ 202	€ 178	€ 166
Cash subject to restrictions		€ 22
Subsidiaries in capital control restrictions countries
Disclosure of cash and cash equivalents [line Items]
Cash subject to restrictions	€ 20

TRADE RECEIVABLES AND OTHER - S

TRADE RECEIVABLES AND OTHER - Schedule of Trade Receivables and Other (Details) - EUR (€) € in Millions	Jun. 30, 2024	Dec. 31, 2023
Non-current
Trade receivables	€ 0	€ 0
Income tax receivables	4	0
Other tax receivables	0	0
Contract assets	17	16
Prepaid expenses	0	0
Other	14	15
Total other receivables	35	31
Total trade receivables and other	35	31
Current
Trade receivables	578	386
Income tax receivables	26	17
Other tax receivables	43	54
Contract assets	2	2
Prepaid expenses	21	8
Other	23	23
Total other receivables	115	104
Total trade receivables and other	693	490
Cost
Non-current
Trade receivables	0	0
Current
Trade receivables	580	388
Impairment
Non-current
Trade receivables	0	0
Current
Trade receivables	€ (2)	€ (2)

TRADE RECEIVABLES AND OTHER - N

TRADE RECEIVABLES AND OTHER - Narrative (Details)	6 Months Ended
	Jun. 30, 2024 EUR (€)	Jun. 30, 2024 USD ($)	Dec. 31, 2023 EUR (€)
Disclosure of trade and other receivables [line items]
Contract assets	€ 17,000,000		€ 16,000,000
Total factored assets	580,000,000		494,000,000
Factored assets derecognized	360,000,000		356,000,000
Debt due factor	1,000,000		1,000,000
Unbilled tooling costs
Disclosure of trade and other receivables [line items]
Contract assets	9,000,000		€ 7,000,000
United States | Factoring of receivables | Muscle Shoals factoring facility
Disclosure of trade and other receivables [line items]
Factoring maximum capacity | $		$ 175,000,000
United States | Factoring of receivables | Constellium automotive
Disclosure of trade and other receivables [line items]
Factoring maximum capacity | $		$ 25,000,000
France | Factoring of receivables
Disclosure of trade and other receivables [line items]
Factoring maximum capacity	250,000,000
France | Factoring Receivable, Recourse Line
Disclosure of trade and other receivables [line items]
Factoring maximum capacity	20,000,000
Germany, Switzerland and Czech Republic | Factoring of receivables
Disclosure of trade and other receivables [line items]
Factoring maximum capacity	€ 200,000,000

TRADE RECEIVABLES AND OTHER - A

TRADE RECEIVABLES AND OTHER - Aging of Total Trade Receivables - Net (Details) - EUR (€) € in Millions	Jun. 30, 2024	Dec. 31, 2023
Trade receivables [line items]
Trade receivables	€ 578	€ 386
Not past due
Trade receivables [line items]
Trade receivables	560	370
1 – 30 days past due
Trade receivables [line items]
Trade receivables	16	15
31 – 60 days past due
Trade receivables [line items]
Trade receivables	1	1
61 – 90 days past due
Trade receivables [line items]
Trade receivables	€ 1	€ 0

TRADE RECEIVABLES AND OTHER - C

TRADE RECEIVABLES AND OTHER - Carrying Amounts of Total Trade Receivables - Net by Currency (Details) - EUR (€) € in Millions	Jun. 30, 2024	Dec. 31, 2023
Trade receivables [line items]
Trade receivables	€ 578	€ 386
Euro
Trade receivables [line items]
Trade receivables	289	167
U.S. Dollars
Trade receivables [line items]
Trade receivables	270	200
Swiss Francs
Trade receivables [line items]
Trade receivables	7	7
Other currencies
Trade receivables [line items]
Trade receivables	€ 12	€ 12

INVENTORIES (Details)

INVENTORIES (Details) - EUR (€) € in Millions	Jun. 30, 2024	Dec. 31, 2023
Subclassifications of assets, liabilities and equities [abstract]
Finished goods	€ 234	€ 260
Work in progress	625	537
Raw materials	203	231
Stores and supplies	128	123
Inventories write down	(56)	(53)
Total inventories	€ 1,134	€ 1,098

PROPERTY, PLANT AND EQUIPMENT_2

PROPERTY, PLANT AND EQUIPMENT (Details) € in Millions	6 Months Ended
	Jun. 30, 2024 EUR (€)
Reconciliation of changes in property, plant and equipment [abstract]
Beginning balance	€ 2,047
Additions	156
Disposals	(2)
Depreciation expense	(141)
Transfer and other changes	(1)
Effect of changes in foreign exchange rates	25
Ending balance	2,084
Cost
Reconciliation of changes in property, plant and equipment [abstract]
Ending balance	4,305
Less accumulated depreciation and impairment
Reconciliation of changes in property, plant and equipment [abstract]
Ending balance	(2,221)
Land and Property Rights
Reconciliation of changes in property, plant and equipment [abstract]
Beginning balance	25
Additions	1
Disposals	0
Depreciation expense	(1)
Transfer and other changes	1
Effect of changes in foreign exchange rates	0
Ending balance	26
Land and Property Rights | Cost
Reconciliation of changes in property, plant and equipment [abstract]
Ending balance	47
Land and Property Rights | Less accumulated depreciation and impairment
Reconciliation of changes in property, plant and equipment [abstract]
Ending balance	(21)
Buildings
Reconciliation of changes in property, plant and equipment [abstract]
Beginning balance	379
Additions	3
Disposals	0
Depreciation expense	(17)
Transfer and other changes	4
Effect of changes in foreign exchange rates	3
Ending balance	372
Buildings | Cost
Reconciliation of changes in property, plant and equipment [abstract]
Ending balance	672
Buildings | Less accumulated depreciation and impairment
Reconciliation of changes in property, plant and equipment [abstract]
Ending balance	(300)
Machinery and Equipment
Reconciliation of changes in property, plant and equipment [abstract]
Beginning balance	1,381
Additions	36
Disposals	(2)
Depreciation expense	(119)
Transfer and other changes	38
Effect of changes in foreign exchange rates	20
Ending balance	1,354
Machinery and Equipment | Cost
Reconciliation of changes in property, plant and equipment [abstract]
Ending balance	3,198
Machinery and Equipment | Less accumulated depreciation and impairment
Reconciliation of changes in property, plant and equipment [abstract]
Ending balance	(1,844)
Construction Work in Progress
Reconciliation of changes in property, plant and equipment [abstract]
Beginning balance	251
Additions	114
Disposals	0
Depreciation expense	0
Transfer and other changes	(46)
Effect of changes in foreign exchange rates	2
Ending balance	321
Construction Work in Progress | Cost
Reconciliation of changes in property, plant and equipment [abstract]
Ending balance	333
Construction Work in Progress | Less accumulated depreciation and impairment
Reconciliation of changes in property, plant and equipment [abstract]
Ending balance	(12)
Other
Reconciliation of changes in property, plant and equipment [abstract]
Beginning balance	11
Additions	2
Disposals	0
Depreciation expense	(4)
Transfer and other changes	2
Effect of changes in foreign exchange rates	0
Ending balance	11
Other | Cost
Reconciliation of changes in property, plant and equipment [abstract]
Ending balance	55
Other | Less accumulated depreciation and impairment
Reconciliation of changes in property, plant and equipment [abstract]
Ending balance	€ (44)

PROPERTY, PLANT AND EQUIPMENT -

PROPERTY, PLANT AND EQUIPMENT - Right of Use Assets (Details) € in Millions	6 Months Ended
	Jun. 30, 2024 EUR (€)
Reconciliation of changes in property, plant and equipment [abstract]
Beginning balance	€ 2,047
Additions	156
Depreciation expense	(141)
Transfer and other changes	(1)
Effect of changes in foreign exchange rates	25
Ending balance	2,084
Cost
Reconciliation of changes in property, plant and equipment [abstract]
Ending balance	4,305
Less accumulated depreciation and impairment
Reconciliation of changes in property, plant and equipment [abstract]
Ending balance	(2,221)
Buildings
Reconciliation of changes in property, plant and equipment [abstract]
Beginning balance	379
Additions	3
Depreciation expense	(17)
Transfer and other changes	4
Effect of changes in foreign exchange rates	3
Ending balance	372
Buildings | Cost
Reconciliation of changes in property, plant and equipment [abstract]
Ending balance	672
Buildings | Less accumulated depreciation and impairment
Reconciliation of changes in property, plant and equipment [abstract]
Ending balance	(300)
Machinery and Equipment
Reconciliation of changes in property, plant and equipment [abstract]
Beginning balance	1,381
Additions	36
Depreciation expense	(119)
Transfer and other changes	38
Effect of changes in foreign exchange rates	20
Ending balance	1,354
Machinery and Equipment | Cost
Reconciliation of changes in property, plant and equipment [abstract]
Ending balance	3,198
Machinery and Equipment | Less accumulated depreciation and impairment
Reconciliation of changes in property, plant and equipment [abstract]
Ending balance	(1,844)
Other
Reconciliation of changes in property, plant and equipment [abstract]
Beginning balance	11
Additions	2
Depreciation expense	(4)
Transfer and other changes	2
Effect of changes in foreign exchange rates	0
Ending balance	11
Other | Cost
Reconciliation of changes in property, plant and equipment [abstract]
Ending balance	55
Other | Less accumulated depreciation and impairment
Reconciliation of changes in property, plant and equipment [abstract]
Ending balance	(44)
Right-of-use assets
Reconciliation of changes in property, plant and equipment [abstract]
Beginning balance	141
Additions	11
Depreciation expense	(12)
Ending balance	140
Right-of-use assets | Cost
Reconciliation of changes in property, plant and equipment [abstract]
Ending balance	279
Right-of-use assets | Less accumulated depreciation and impairment
Reconciliation of changes in property, plant and equipment [abstract]
Ending balance	(139)
Right-of-use assets | Buildings
Reconciliation of changes in property, plant and equipment [abstract]
Beginning balance	103
Additions	3
Depreciation expense	(6)
Ending balance	100
Right-of-use assets | Buildings | Cost
Reconciliation of changes in property, plant and equipment [abstract]
Ending balance	172
Right-of-use assets | Buildings | Less accumulated depreciation and impairment
Reconciliation of changes in property, plant and equipment [abstract]
Ending balance	(72)
Right-of-use assets | Machinery and Equipment
Reconciliation of changes in property, plant and equipment [abstract]
Beginning balance	38
Additions	8
Depreciation expense	(6)
Ending balance	40
Right-of-use assets | Machinery and Equipment | Cost
Reconciliation of changes in property, plant and equipment [abstract]
Ending balance	107
Right-of-use assets | Machinery and Equipment | Less accumulated depreciation and impairment
Reconciliation of changes in property, plant and equipment [abstract]
Ending balance	(67)
Right-of-use assets | Other
Reconciliation of changes in property, plant and equipment [abstract]
Beginning balance	0
Additions	0
Depreciation expense	0
Ending balance	0
Right-of-use assets | Other | Cost
Reconciliation of changes in property, plant and equipment [abstract]
Ending balance	0
Right-of-use assets | Other | Less accumulated depreciation and impairment
Reconciliation of changes in property, plant and equipment [abstract]
Ending balance	€ 0

PROPERTY, PLANT AND EQUIPMENT_3

PROPERTY, PLANT AND EQUIPMENT - Narrative (Details) - EUR (€) € in Millions	6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023
Property, plant and equipment [abstract]
Expense related to short-term leases, low value asset leases and variable lease still recognized as operating expenses	€ 9	€ 8

INTANGIBLE ASSETS AND GOODWIL_2

INTANGIBLE ASSETS AND GOODWILL - Changes in Intangible Assets and Goodwill (Details) € in Millions	6 Months Ended
	Jun. 30, 2024 EUR (€)
Changes in intangible assets other than goodwill [abstract]
Intangible assets (excluding goodwill), beginning balance	€ 47
Additions	1
Amortization expense	(4)
Effect of changes in foreign exchange rates	1
Intangible assets (excluding goodwill), ending balance	45
Changes in goodwill [abstract]
Goodwill, beginning balance	462
Effect of changes in foreign exchange rates	15
Goodwill, ending balance	477
Acquired through business combination	0
Cost
Changes in intangible assets other than goodwill [abstract]
Intangible assets (excluding goodwill), ending balance	230
Changes in goodwill [abstract]
Goodwill, ending balance	477
Less accumulated depreciation and impairment
Changes in intangible assets other than goodwill [abstract]
Intangible assets (excluding goodwill), ending balance	(185)
Changes in goodwill [abstract]
Goodwill, ending balance	0
Technology
Changes in intangible assets other than goodwill [abstract]
Intangible assets (excluding goodwill), beginning balance	16
Additions	0
Amortization expense	(1)
Effect of changes in foreign exchange rates	1
Intangible assets (excluding goodwill), ending balance	16
Technology | Cost
Changes in intangible assets other than goodwill [abstract]
Intangible assets (excluding goodwill), ending balance	92
Technology | Less accumulated depreciation and impairment
Changes in intangible assets other than goodwill [abstract]
Intangible assets (excluding goodwill), ending balance	(76)
Computer Software
Changes in intangible assets other than goodwill [abstract]
Intangible assets (excluding goodwill), beginning balance	13
Additions	0
Amortization expense	(2)
Effect of changes in foreign exchange rates	0
Intangible assets (excluding goodwill), ending balance	11
Computer Software | Cost
Changes in intangible assets other than goodwill [abstract]
Intangible assets (excluding goodwill), ending balance	88
Computer Software | Less accumulated depreciation and impairment
Changes in intangible assets other than goodwill [abstract]
Intangible assets (excluding goodwill), ending balance	(77)
Customer relationships
Changes in intangible assets other than goodwill [abstract]
Intangible assets (excluding goodwill), beginning balance	12
Additions	0
Amortization expense	0
Effect of changes in foreign exchange rates	0
Intangible assets (excluding goodwill), ending balance	12
Customer relationships | Cost
Changes in intangible assets other than goodwill [abstract]
Intangible assets (excluding goodwill), ending balance	42
Customer relationships | Less accumulated depreciation and impairment
Changes in intangible assets other than goodwill [abstract]
Intangible assets (excluding goodwill), ending balance	(30)
Work in Progress
Changes in intangible assets other than goodwill [abstract]
Intangible assets (excluding goodwill), beginning balance	3
Additions	1
Amortization expense	(1)
Effect of changes in foreign exchange rates	0
Intangible assets (excluding goodwill), ending balance	3
Work in Progress | Cost
Changes in intangible assets other than goodwill [abstract]
Intangible assets (excluding goodwill), ending balance	4
Work in Progress | Less accumulated depreciation and impairment
Changes in intangible assets other than goodwill [abstract]
Intangible assets (excluding goodwill), ending balance	(1)
Other
Changes in intangible assets other than goodwill [abstract]
Intangible assets (excluding goodwill), beginning balance	3
Additions	0
Amortization expense	0
Effect of changes in foreign exchange rates	0
Intangible assets (excluding goodwill), ending balance	3
Other | Cost
Changes in intangible assets other than goodwill [abstract]
Intangible assets (excluding goodwill), ending balance	4
Other | Less accumulated depreciation and impairment
Changes in intangible assets other than goodwill [abstract]
Intangible assets (excluding goodwill), ending balance	€ (1)

DISPOSAL GROUPS CLASSIFIED AS H

DISPOSAL GROUPS CLASSIFIED AS HELD FOR SALE - Narrative (Details) - EUR (€) € in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Disclosure of analysis of single amount of discontinued operations [line items]
Losses on disposal	€ 0	€ 0	€ (1)	€ (6)
Disposal groups classified as held for sale
Disclosure of analysis of single amount of discontinued operations [line items]
Losses on disposal			€ 5

DISPOSAL GROUPS CLASSIFIED AS_2

DISPOSAL GROUPS CLASSIFIED AS HELD FOR SALE - Assets and Liabilities (Details) - EUR (€) € in Millions	Jun. 30, 2024	Dec. 31, 2023	Jun. 30, 2023	Dec. 31, 2022
Disclosure of analysis of single amount of discontinued operations [line items]
Cash and cash equivalents	€ 213	€ 202	€ 178	€ 166
Trade receivables and other	693	490
Inventories	1,134	1,098
Property, plant and equipment	2,084	2,047
Deferred tax assets	234	252
Trade payables and other	1,431	1,263
Pension and other post-employment benefit obligations	€ 380	€ 411

TRADE PAYABLES AND OTHER (Detai

TRADE PAYABLES AND OTHER (Details) - EUR (€) € in Millions	Jun. 30, 2024	Dec. 31, 2023
Non-current
Trade payables	€ 0	€ 0
Fixed assets payables	0	0
Employees' entitlements	0	0
Taxes payable other than income tax	0	0
Contract liabilities and other liabilities to customers	31	29
Other payables	37	30
Total other	68	59
Total trade payables and other	68	59
Current
Trade payables	1,099	931
Fixed assets payables	41	35
Employees' entitlements	195	211
Taxes payable other than income tax	32	15
Contract liabilities and other liabilities to customers	54	62
Other payables	10	9
Total other	332	332
Total trade payables and other	€ 1,431	€ 1,263

TRADE PAYABLES AND OTHER - Cont

TRADE PAYABLES AND OTHER - Contract Liabilities (Details) - EUR (€) € in Millions	Jun. 30, 2024	Dec. 31, 2023
Disclosure of disaggregation of revenue from contracts with customers [line items]
Non-current	€ 31	€ 29
Current	54	62
Deferred tooling revenue
Disclosure of disaggregation of revenue from contracts with customers [line items]
Non-current	30	28
Current	0	0
Advance payment from customers
Disclosure of disaggregation of revenue from contracts with customers [line items]
Non-current	0	0
Current	12	7
Unrecognized variable consideration
Disclosure of disaggregation of revenue from contracts with customers [line items]
Non-current	1	1
Current	€ 42	€ 55

TRADE PAYABLES AND OTHER - Narr

TRADE PAYABLES AND OTHER - Narrative (Details) - EUR (€) € in Millions	6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023
Trade and other payables [abstract]
Revenue recognized related to contract liabilities	€ 24	€ 11
Deferred revenue related to contract liabilities	€ 15	€ 27

BORROWINGS - Borrowings by Natu

BORROWINGS - Borrowings by Nature (Details)		6 Months Ended
	Jul. 20, 2023 EUR (€)	Jun. 30, 2024 EUR (€)	Jun. 30, 2024 USD ($)	Dec. 31, 2023 EUR (€)	Dec. 31, 2022 EUR (€)
Disclosure of detailed information about borrowings [line items]
Nominal value		€ 1,888,000,000
Gross lease liabilities		151,000,000
Arrangement fees		(14,000,000)
Lease Arrangement Fees		0
Accrued interests		21,000,000
Accrued interest lease liabilities		1,000,000
Total Borrowings		1,895,000,000		€ 1,868,000,000	€ 2,056,000,000
Lease liabilities		152,000,000		154,000,000
Non-current borrowings		1,842,000,000		1,814,000,000
Current borrowings		53,000,000		54,000,000
Secured Pan-U.S. ABL (due 2026)
Disclosure of detailed information about borrowings [line items]
Borrowing base		467,000,000	$ 500,000,000
Secured French PGE French Facility (due 2022)
Disclosure of detailed information about borrowings [line items]
Borrowing base | $			100,000,000
Senior Unsecured Notes due 2026
Disclosure of detailed information about borrowings [line items]
Nominal value		€ 234,000,000	250,000,000
Nominal rate	5.875%	5.875%
Arrangement fees		€ (1,000,000)
Accrued interests		5,000,000
Total Borrowings	€ 300,000,000	238,000,000		230,000,000
Senior Unsecured Note due 2026
Disclosure of detailed information about borrowings [line items]
Nominal value		€ 400,000,000
Nominal rate		4.25%
Arrangement fees		€ (2,000,000)
Accrued interests		6,000,000
Total Borrowings		404,000,000		404,000,000
Senior Unscured Notes due 2028
Disclosure of detailed information about borrowings [line items]
Nominal value		€ 303,000,000	325,000,000
Nominal rate		5.625%
Arrangement fees		€ (3,000,000)
Accrued interests		1,000,000
Total Borrowings		301,000,000		291,000,000
Sustainability-Linked Senior Notes Issued February 2021 Due 2029
Disclosure of detailed information about borrowings [line items]
Nominal value		€ 467,000,000	$ 500,000,000
Nominal rate		3.75%
Arrangement fees		€ (5,000,000)
Accrued interests		4,000,000
Total Borrowings		466,000,000		452,000,000
Sustainability-Link Senior Notes Issued June 2021 due 2029
Disclosure of detailed information about borrowings [line items]
Nominal value		€ 300,000,000
Nominal rate		3.125%
Arrangement fees		€ (3,000,000)
Accrued interests		4,000,000
Total Borrowings		301,000,000		300,000,000
Other loans
Disclosure of detailed information about borrowings [line items]
Nominal value		33,000,000
Arrangement fees		0
Accrued interests		0
Total Borrowings		33,000,000		€ 37,000,000
Financing Arrangements
Disclosure of detailed information about borrowings [line items]
Total Borrowings		€ 28,000,000

BORROWINGS - Narrative (Details

BORROWINGS - Narrative (Details) € in Millions	Jun. 30, 2024 EUR (€)
Disclosure of detailed information about borrowings [line items]
Undrawn facilities	€ 656
Secured Inventory Facility
Disclosure of detailed information about borrowings [line items]
Undrawn facilities	100
Money Market Facility
Disclosure of detailed information about borrowings [line items]
Undrawn facilities	€ 75

BORROWINGS - Movement in Borrow

BORROWINGS - Movement in Borrowings (Details)		6 Months Ended		12 Months Ended
	Jul. 20, 2023 EUR (€)	Jun. 30, 2024 EUR (€)	Jun. 30, 2023 EUR (€)	Dec. 31, 2023 EUR (€)	Jun. 30, 2024 USD ($)
Disclosure of detailed information about borrowings [line items]
At January 1,		€ 1,868,000,000	€ 2,056,000,000	€ 2,056,000,000
Cash flows
Repayments of long-term borrowings		(4,000,000)	(5,000,000)	(53,000,000)
Net change in revolving credit facilities and short-term borrowings		0	€ 7,000,000	(83,000,000)
Lease repayments		(13,000,000)		(37,000,000)
Non-cash changes
Movement in accrued interest		0		(1,000,000)
Changes in leases and other loans		9,000,000		24,000,000
Deferred arrangement fees		2,000,000		4,000,000
Effects of changes in foreign exchange rates		33,000,000		(42,000,000)
At the end of the period		1,895,000,000		1,868,000,000
Nominal value		1,888,000,000
Amount drawn under credit facility		1,895,000,000		1,868,000,000
Sustainability-Linked Senior Notes Issued February 2021 Due 2029
Disclosure of detailed information about borrowings [line items]
At January 1,		452,000,000
Non-cash changes
At the end of the period		466,000,000		452,000,000
Nominal value		467,000,000			$ 500,000,000
Amount drawn under credit facility		€ 466,000,000		452,000,000
Nominal rate		3.75%
Sustainability-Link Senior Notes Issued June 2021 due 2029
Disclosure of detailed information about borrowings [line items]
At January 1,		€ 300,000,000
Non-cash changes
At the end of the period		301,000,000		300,000,000
Nominal value		300,000,000
Amount drawn under credit facility		€ 301,000,000		300,000,000
Nominal rate		3.125%
Senior Unsecured Notes due 2026
Disclosure of detailed information about borrowings [line items]
At January 1,		€ 230,000,000
Non-cash changes
At the end of the period	€ 300,000,000	238,000,000		230,000,000
Proceeds from issuance of long-term borrowings	50,000,000
Nominal value		234,000,000			$ 250,000,000
Amount drawn under credit facility	€ 300,000,000	€ 238,000,000		€ 230,000,000
Nominal rate	5.875%	5.875%

BORROWINGS - Currency Concentra

BORROWINGS - Currency Concentration of Total Borrowings (Details) - EUR (€) € in Millions	Jun. 30, 2024	Dec. 31, 2023	Dec. 31, 2022
Disclosure of detailed information about borrowings [line items]
Total Borrowings	€ 1,895	€ 1,868	€ 2,056
U.S. Dollars
Disclosure of detailed information about borrowings [line items]
Total Borrowings	1,044	1,012
Euro
Disclosure of detailed information about borrowings [line items]
Total Borrowings	845	849
Other currencies
Disclosure of detailed information about borrowings [line items]
Total Borrowings	€ 6	€ 7

FINANCIAL INSTRUMENTS - Financi

FINANCIAL INSTRUMENTS - Financial Assets and Liabilities by Categories (Details) - EUR (€) € in Millions	Jun. 30, 2024	Dec. 31, 2023
Disclosure of detailed information about financial instruments [line items]
Financial assets	€ 815	€ 620
Financial liabilities	3,076	2,876
Trade payables and fixed asset payables
Disclosure of detailed information about financial instruments [line items]
Financial liabilities	1,140	966
Borrowings
Disclosure of detailed information about financial instruments [line items]
Financial liabilities	1,895	1,868
Other financial liabilities
Disclosure of detailed information about financial instruments [line items]
Financial liabilities	41	42
At amortized cost
Disclosure of detailed information about financial instruments [line items]
Financial liabilities	3,035	2,834
At amortized cost | Trade payables and fixed asset payables
Disclosure of detailed information about financial instruments [line items]
Financial liabilities	1,140	966
At amortized cost | Borrowings
Disclosure of detailed information about financial instruments [line items]
Financial liabilities	1,895	1,868
At amortized cost | Other financial liabilities
Disclosure of detailed information about financial instruments [line items]
Financial liabilities	0	0
At fair value through profit and loss
Disclosure of detailed information about financial instruments [line items]
Financial liabilities	31	35
At fair value through profit and loss | Trade payables and fixed asset payables
Disclosure of detailed information about financial instruments [line items]
Financial liabilities	0	0
At fair value through profit and loss | Borrowings
Disclosure of detailed information about financial instruments [line items]
Financial liabilities	0	0
At fair value through profit and loss | Other financial liabilities
Disclosure of detailed information about financial instruments [line items]
Financial liabilities	31	35
At fair value through OCI
Disclosure of detailed information about financial instruments [line items]
Financial liabilities	10	7
At fair value through OCI | Trade payables and fixed asset payables
Disclosure of detailed information about financial instruments [line items]
Financial liabilities	0	0
At fair value through OCI | Borrowings
Disclosure of detailed information about financial instruments [line items]
Financial liabilities	0	0
At fair value through OCI | Other financial liabilities
Disclosure of detailed information about financial instruments [line items]
Financial liabilities	10	7
Cash and cash equivalents
Disclosure of detailed information about financial instruments [line items]
Financial assets	213	202
Trade receivables
Disclosure of detailed information about financial instruments [line items]
Financial assets	578	386
Other financial assets
Disclosure of detailed information about financial instruments [line items]
Financial assets	24	32
At amortized cost
Disclosure of detailed information about financial instruments [line items]
Financial assets	213	202
At amortized cost | Cash and cash equivalents
Disclosure of detailed information about financial instruments [line items]
Financial assets	213	202
At amortized cost | Trade receivables
Disclosure of detailed information about financial instruments [line items]
Financial assets	0	0
At amortized cost | Other financial assets
Disclosure of detailed information about financial instruments [line items]
Financial assets	0	0
At fair value through profit and loss
Disclosure of detailed information about financial instruments [line items]
Financial assets	24	31
At fair value through profit and loss | Cash and cash equivalents
Disclosure of detailed information about financial instruments [line items]
Financial assets	0	0
At fair value through profit and loss | Trade receivables
Disclosure of detailed information about financial instruments [line items]
Financial assets	0	0
At fair value through profit and loss | Other financial assets
Disclosure of detailed information about financial instruments [line items]
Financial assets	24	31
At fair value through OCI
Disclosure of detailed information about financial instruments [line items]
Financial assets	578	387
At fair value through OCI | Cash and cash equivalents
Disclosure of detailed information about financial instruments [line items]
Financial assets	0	0
At fair value through OCI | Trade receivables
Disclosure of detailed information about financial instruments [line items]
Financial assets	578	386
At fair value through OCI | Other financial assets
Disclosure of detailed information about financial instruments [line items]
Financial assets	€ 0	€ 1

FINANCIAL INSTRUMENTS - Narrati

FINANCIAL INSTRUMENTS - Narrative (Details) - Fair value - Level 1 € in Millions	Jun. 30, 2024 EUR (€)
Constellium SE Senior Notes Due 2024
Disclosure of detailed information about financial instruments [line items]
Percentage of fair value senior notes issued	99.50%
Senior notes issued	€ 631
Constellium SE Senior Unsecured Notes Ddue 2025
Disclosure of detailed information about financial instruments [line items]
Percentage of fair value senior notes issued	97.80%
Senior notes issued	€ 297
Constellium SE Senior Notes Due 2026
Disclosure of detailed information about financial instruments [line items]
Percentage of fair value senior notes issued	90.40%
Senior notes issued	€ 422
Constellium SE Senir Notes Due 2028
Disclosure of detailed information about financial instruments [line items]
Percentage of fair value senior notes issued	93.40%
Senior notes issued	€ 280

FINANCIAL INSTRUMENTS - Other F

FINANCIAL INSTRUMENTS - Other Financial Assets and Other Financial Liabilities Positions (Details) - EUR (€)	Jun. 30, 2024	Dec. 31, 2023
Disclosure of detailed information about financial instruments [line items]
Non-current derivatives assets	€ 2,000,000	€ 2,000,000
Current derivatives assets	22,000,000	30,000,000
Derivative financial assets	24,000,000	32,000,000
Non-current derivatives liabilities	11,000,000	8,000,000
Current derivative liabilities	30,000,000	34,000,000
Derivatives liabilities	41,000,000	42,000,000
Aluminium and premium derivatives
Disclosure of detailed information about financial instruments [line items]
Non-current derivatives liabilities	1,000,000	1,000,000
Current derivative liabilities	6,000,000	9,000,000
Derivatives liabilities	7,000,000	10,000,000
Energy derivatives
Disclosure of detailed information about financial instruments [line items]
Non-current derivatives liabilities	1,000,000	3,000,000
Current derivative liabilities	6,000,000	9,000,000
Derivatives liabilities	7,000,000	12,000,000
Other commodity derivatives
Disclosure of detailed information about financial instruments [line items]
Non-current derivatives liabilities	0	0
Current derivative liabilities	1,000,000	2,000,000
Derivatives liabilities	1,000,000	2,000,000
Currency commercial derivatives
Disclosure of detailed information about financial instruments [line items]
Non-current derivatives liabilities	9,000,000	4,000,000
Current derivative liabilities	17,000,000	14,000,000
Derivatives liabilities	26,000,000	18,000,000
Aluminium and premium derivatives
Disclosure of detailed information about financial instruments [line items]
Non-current derivatives assets	2,000,000	1,000,000
Current derivatives assets	15,000,000	17,000,000
Derivative financial assets	17,000,000	18,000,000
Other commodity derivatives
Disclosure of detailed information about financial instruments [line items]
Non-current derivatives assets	0	0
Current derivatives assets	4,000,000	1,000,000
Derivative financial assets	4,000,000	1,000,000
Currency commercial derivatives
Disclosure of detailed information about financial instruments [line items]
Non-current derivatives assets	0	1,000,000
Current derivatives assets	3,000,000	10,000,000
Derivative financial assets	3,000,000	11,000,000
Currency net debt derivatives
Disclosure of detailed information about financial instruments [line items]
Non-current derivatives assets	0	0
Current derivatives assets	0	2,000,000
Derivative financial assets	0	2,000,000
Margin call
Disclosure of detailed information about financial instruments [line items]
Current derivatives assets	€ 0	€ 0

FINANCIAL INSTRUMENTS - Derivat

FINANCIAL INSTRUMENTS - Derivatives Measured at Fair Value (Details) - EUR (€) € in Millions	Jun. 30, 2024	Dec. 31, 2023
Disclosure of financial instruments measured at fair value [line items]
Other financial assets - derivatives	€ 24	€ 32
Other financial liabilities - derivatives	41	42
Level 1
Disclosure of financial instruments measured at fair value [line items]
Other financial assets - derivatives	15	17
Other financial liabilities - derivatives	6	7
Level 2
Disclosure of financial instruments measured at fair value [line items]
Other financial assets - derivatives	9	15
Other financial liabilities - derivatives	35	35
Level 3
Disclosure of financial instruments measured at fair value [line items]
Other financial assets - derivatives	0	0
Other financial liabilities - derivatives	€ 0	€ 0

FINANCIAL RISK MANAGEMENT - Nar

FINANCIAL RISK MANAGEMENT - Narrative (Details) $ in Millions	Jun. 30, 2024 EUR (€)	Jun. 30, 2024 USD ($)	Dec. 31, 2023 EUR (€)	Dec. 31, 2023 USD ($)	Jun. 30, 2023 EUR (€)	Dec. 31, 2022 EUR (€)
Disclosure of liquidity risk [line items]
Revolving credit facilities outstanding availability	€ 552,000,000
Liquidity value	869,000,000
Cash and cash equivalents	213,000,000		€ 202,000,000		€ 178,000,000	€ 166,000,000
Undrawn facilities	656,000,000
Margin requirement	22,000,000		30,000,000
Margin call
Disclosure of liquidity risk [line items]
Margin requirement	0		€ 0
Derivative classified as cash flow hedge
Disclosure of liquidity risk [line items]
Nominal amount hedging instrument | $		$ 470		$ 209
U.S. Revolving Facility
Disclosure of liquidity risk [line items]
Borrowing base	€ 467,000,000	500
French Inventory Based Facility
Disclosure of liquidity risk [line items]
Borrowing base | $		$ 100

FINANCIAL RISK MANAGEMENT - Eff

FINANCIAL RISK MANAGEMENT - Effect of Foreign Currency Derivatives Impacts and Commercial Transactions Exposures (Details) - EUR (€) € in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Disclosure of nature and extent of risks arising from financial instruments [line items]
Realized (losses) / gains on foreign currency derivatives - net	€ (4)	€ 4	€ (8)	€ 6
Unrealized (losses) / gains on foreign currency derivatives - net	(3)	(6)	(12)	(3)
Derivatives that do not qualify for hedge accounting | At fair value through profit and loss
Disclosure of nature and extent of risks arising from financial instruments [line items]
Realized (losses) / gains on foreign currency derivatives - net	(2)	5	(4)	9
Unrealized (losses) / gains on foreign currency derivatives - net	(3)	(6)	(11)	(4)
Derivatives that qualify for hedge accounting | At fair value through profit and loss
Disclosure of nature and extent of risks arising from financial instruments [line items]
Realized (losses) / gains on foreign currency derivatives - net	(2)	(1)	(4)	(3)
Unrealized (losses) / gains on foreign currency derivatives - net	0	0	(1)	1
Derivatives that qualify for hedge accounting | At fair value through OCI
Disclosure of nature and extent of risks arising from financial instruments [line items]
Unrealized (losses) / gains on foreign currency derivatives - net	(5)	0	(9)	2
Gains reclassified from cash flow hedge reserve to the Consolidated Income Statement	€ 3	€ 1	€ 5	€ 2

PENSIONS AND OTHER POST-EMPLO_3

PENSIONS AND OTHER POST-EMPLOYMENT BENEFIT OBLIGATIONS - Actuarial Assumptions (Details)	Jun. 30, 2024	Dec. 31, 2023
Switzerland
Disclosure of sensitivity analysis for actuarial assumptions [line items]
Discount rate	1.45%	1.40%
U.S. | Hourly pension | Bottom of range
Disclosure of sensitivity analysis for actuarial assumptions [line items]
Discount rate	5.30%	4.85%
U.S. | Hourly pension | Top of range
Disclosure of sensitivity analysis for actuarial assumptions [line items]
Discount rate	5.35%	4.90%
U.S. | Salaried pension
Disclosure of sensitivity analysis for actuarial assumptions [line items]
Discount rate	5.35%	4.85%
U.S. | OPEB | Bottom of range
Disclosure of sensitivity analysis for actuarial assumptions [line items]
Discount rate	5.30%	4.85%
U.S. | OPEB | Top of range
Disclosure of sensitivity analysis for actuarial assumptions [line items]
Discount rate	5.40%	4.90%
U.S. | Other benefits | Bottom of range
Disclosure of sensitivity analysis for actuarial assumptions [line items]
Discount rate	5.25%	4.75%
U.S. | Other benefits | Top of range
Disclosure of sensitivity analysis for actuarial assumptions [line items]
Discount rate	5.30%	4.85%
France | Retirements
Disclosure of sensitivity analysis for actuarial assumptions [line items]
Discount rate	3.65%	3.30%
France | Other benefits
Disclosure of sensitivity analysis for actuarial assumptions [line items]
Discount rate	3.60%	3.25%
Germany
Disclosure of sensitivity analysis for actuarial assumptions [line items]
Discount rate	3.65%	3.30%

PENSIONS AND OTHER POST-EMPLO_4

PENSIONS AND OTHER POST-EMPLOYMENT BENEFIT OBLIGATIONS - Amounts Recognized in the Consolidated Statement of Financial Position (Details) € in Millions, $ in Millions	Jun. 30, 2024 EUR (€)	Dec. 31, 2023 EUR (€)	Dec. 31, 2023 USD ($)
Disclosure of net defined benefit liability (asset) [line items]
Fair value of plan assets	€ (492)	€ (488)
Net defined benefit liability	380	411	$ 411
Of which net liability	380	411
Funded
Disclosure of net defined benefit liability (asset) [line items]
Present value of obligation	629	653
Fair value of plan assets	(492)	(488)
Deficit of funded plans	137	165
Unfunded
Disclosure of net defined benefit liability (asset) [line items]
Present value of obligation	243	246
Pension Benefits
Disclosure of net defined benefit liability (asset) [line items]
Net defined benefit liability	241	268
Pension Benefits | Funded
Disclosure of net defined benefit liability (asset) [line items]
Present value of obligation	629	653
Fair value of plan assets	(492)	(488)
Deficit of funded plans	137	165
Pension Benefits | Unfunded
Disclosure of net defined benefit liability (asset) [line items]
Present value of obligation	104	103
Other Benefits
Disclosure of net defined benefit liability (asset) [line items]
Net defined benefit liability	139	143
Other Benefits | Funded
Disclosure of net defined benefit liability (asset) [line items]
Present value of obligation	0	0
Fair value of plan assets	0	0
Deficit of funded plans	0	0
Other Benefits | Unfunded
Disclosure of net defined benefit liability (asset) [line items]
Present value of obligation	€ 139	€ 143

PENSIONS AND OTHER POST-EMPLO_5

PENSIONS AND OTHER POST-EMPLOYMENT BENEFIT OBLIGATIONS - Amounts Recognized in the Consolidated Income Statement (Details) - EUR (€) € in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Disclosure of defined benefit plans [line items]
Current service cost	€ (5)	€ (5)	€ (10)	€ (10)
Net interest	(5)	(4)	(8)	(8)
Immediate recognition of gains arising over the year	1	0	1	0
Administration expenses	0	0	(1)	(1)
Total	(9)	(9)	(18)	(19)
Pension Benefits
Disclosure of defined benefit plans [line items]
Current service cost	(4)	(3)	(8)	(7)
Net interest	(3)	(3)	(4)	(5)
Immediate recognition of gains arising over the year	0	0	0	0
Administration expenses	0	0	(1)	(1)
Total	(7)	(6)	(13)	(13)
Other Benefits
Disclosure of defined benefit plans [line items]
Current service cost	(1)	(2)	(2)	(3)
Net interest	(2)	(1)	(4)	(3)
Immediate recognition of gains arising over the year	1	0	1	0
Administration expenses	0	0	0	0
Total	€ (2)	€ (3)	€ (5)	€ (6)

PENSIONS AND OTHER POST-EMPLO_6

PENSIONS AND OTHER POST-EMPLOYMENT BENEFIT OBLIGATIONS - Movement in Net Defined Benefit Obligations (Details) € in Millions, $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2024 EUR (€)	Jun. 30, 2023 EUR (€)	Jun. 30, 2024 EUR (€)	Jun. 30, 2024 USD ($)	Jun. 30, 2023 EUR (€)
Disclosure of net defined benefit liability (asset) [line items]
At January 1, 2024			€ 411	$ 411
Current service cost	€ 5	€ 5	10		€ 10
Interest cost / (income)	5	4	8		8
Immediate recognition of losses arising over the year	(1)	0	(1)		0
Administration expenses	0	0	1		1
Remeasurements due to:
—actual return less interest on plan assets			(9)
—changes in financial assumptions			(26)
—changes in demographic assumptions			0
—experience losses			2
Effects of changes in foreign exchange rates			4
Benefits paid			(11)
Contributions by the Group			(9)
Contributions by the plan participants			0
At June 30, 2024	380		380
Pension Benefits
Disclosure of net defined benefit liability (asset) [line items]
At January 1, 2024			268
Current service cost	4	3	8		7
Interest cost / (income)	3	3	4		5
Immediate recognition of losses arising over the year	0	0	0		0
Administration expenses	0	0	1		1
Remeasurements due to:
At June 30, 2024	241		241
Other Benefits
Disclosure of net defined benefit liability (asset) [line items]
At January 1, 2024			143
Current service cost	1	2	2		3
Interest cost / (income)	2	1	4		3
Immediate recognition of losses arising over the year	(1)	0	(1)		0
Administration expenses	0	€ 0	0		€ 0
Remeasurements due to:
At June 30, 2024	139		139
Defined benefit obligations
Disclosure of net defined benefit liability (asset) [line items]
At January 1, 2024			899
Current service cost			10
Interest cost / (income)			15
Immediate recognition of losses arising over the year			(1)
Administration expenses			0
Remeasurements due to:
—actual return less interest on plan assets			0
—changes in financial assumptions			(26)
—changes in demographic assumptions			0
—experience losses			2
Effects of changes in foreign exchange rates			1
Benefits paid			(30)
Contributions by the Group			0
Contributions by the plan participants			2
At June 30, 2024	872		872
Defined benefit obligations | Pension Benefits
Disclosure of net defined benefit liability (asset) [line items]
At January 1, 2024			756
Current service cost			8
Interest cost / (income)			11
Immediate recognition of losses arising over the year			0
Administration expenses			0
Remeasurements due to:
—actual return less interest on plan assets			0
—changes in financial assumptions			(21)
—changes in demographic assumptions			0
—experience losses			1
Effects of changes in foreign exchange rates			(2)
Benefits paid			(22)
Contributions by the Group			0
Contributions by the plan participants			2
At June 30, 2024	733		733
Defined benefit obligations | Other Benefits
Disclosure of net defined benefit liability (asset) [line items]
At January 1, 2024			143
Current service cost			2
Interest cost / (income)			4
Immediate recognition of losses arising over the year			(1)
Administration expenses			0
Remeasurements due to:
—actual return less interest on plan assets			0
—changes in financial assumptions			(5)
—changes in demographic assumptions			0
—experience losses			1
Effects of changes in foreign exchange rates			3
Benefits paid			(8)
Contributions by the Group			0
Contributions by the plan participants			0
At June 30, 2024	139		139
Plan Assets
Disclosure of net defined benefit liability (asset) [line items]
At January 1, 2024			(488)
Current service cost			0
Interest cost / (income)			(7)
Immediate recognition of losses arising over the year			0
Administration expenses			1
Remeasurements due to:
—actual return less interest on plan assets			(9)
—changes in financial assumptions			0
—changes in demographic assumptions			0
—experience losses			0
Effects of changes in foreign exchange rates			3
Benefits paid			19
Contributions by the Group			(9)
Contributions by the plan participants			(2)
At June 30, 2024	€ (492)		€ (492)

PENSIONS AND OTHER POST-EMPLO_7

PENSIONS AND OTHER POST-EMPLOYMENT BENEFIT OBLIGATIONS - Net Defined Benefit Obligations by Country (Details) € in Millions, $ in Millions	Jun. 30, 2024 EUR (€)	Dec. 31, 2023 EUR (€)	Dec. 31, 2023 USD ($)
Disclosure of net defined benefit liability (asset) [line items]
Defined benefit obligations	€ 872	€ 899
Plan assets	(492)	(488)
Net defined benefit liability	380	411	$ 411
France
Disclosure of net defined benefit liability (asset) [line items]
Defined benefit obligations	126	127
Plan assets	(6)	(6)
Net defined benefit liability	120	121
Germany
Disclosure of net defined benefit liability (asset) [line items]
Defined benefit obligations	97	103
Plan assets	(1)	(1)
Net defined benefit liability	96	102
Switzerland
Disclosure of net defined benefit liability (asset) [line items]
Defined benefit obligations	277	290
Plan assets	(267)	(265)
Net defined benefit liability	10	25
United States
Disclosure of net defined benefit liability (asset) [line items]
Defined benefit obligations	372	379
Plan assets	(218)	(216)
Net defined benefit liability	€ 154	€ 163

PROVISIONS - Changes in Provisi

PROVISIONS - Changes in Provisions (Details) - EUR (€) € in Millions	6 Months Ended
	Jun. 30, 2024	Dec. 31, 2023
Changes in other provisions [abstract]
At January 1, 2024	€ 107
Allowance	1
Amounts used	(1)
Unused amounts reversed	(2)
Effects of changes in foreign exchange rates	0
At June 30, 2024	105
Of which non-current	86	€ 89
Of which current	19	18
Total provisions	105	107
Close down and environmental remediation costs
Changes in other provisions [abstract]
At January 1, 2024	86
Allowance	0
Amounts used	(1)
Unused amounts reversed	0
Effects of changes in foreign exchange rates	0
At June 30, 2024	85
Of which non-current	75
Of which current	10
Total provisions	85	86
Restructuring costs
Changes in other provisions [abstract]
At January 1, 2024	0
Allowance	1
Amounts used	0
Unused amounts reversed	0
Effects of changes in foreign exchange rates	0
At June 30, 2024	1
Of which non-current	0
Of which current	1
Total provisions	1	0
Legal claims and other costs
Changes in other provisions [abstract]
At January 1, 2024	21
Allowance	0
Amounts used	0
Unused amounts reversed	(2)
Effects of changes in foreign exchange rates	0
At June 30, 2024	19
Of which non-current	11
Of which current	8
Total provisions	€ 19	€ 21

PROVISIONS - Legal Claims and O

PROVISIONS - Legal Claims and Other Costs (Details) - Legal claims and other costs - EUR (€) € in Millions	Jun. 30, 2024	Dec. 31, 2023
Disclosure of other provisions [line items]
Litigation	€ 11	€ 13
Disease claims	8	8
Total provisions for legal claims and other costs	€ 19	€ 21

NON-CASH INVESTING AND FINANC_2

NON-CASH INVESTING AND FINANCING TRANSACTIONS (Details) - EUR (€) € in Millions	6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023
Disclosure of cash flow statement [Abstract]
Property, plant and equipment acquired by finance lease	€ 9	€ 7
Fair value of vested PSUs and RSUs	€ 19	€ 10

SHARE CAPITAL - Narrative (Deta

SHARE CAPITAL - Narrative (Details)	Jun. 30, 2024 EUR (€) € / shares shares	Dec. 31, 2023 EUR (€) shares
Disclosure of classes of share capital [line items]
Share capital | €	€ 2,936,397.68	€ 3,000,000
Nominal value of ordinary fully-paid shares (in EUR per share) | € / shares	€ 0.02
Number of vote rights per share	1
Ordinary shares
Disclosure of classes of share capital [line items]
Number of ordinary shares (in shares) | shares	146,819,884	146,819,884

SHARE CAPITAL (Details)

SHARE CAPITAL (Details) - EUR (€) € in Millions	Jun. 30, 2024	Dec. 31, 2023	Jun. 30, 2023
Disclosure of classes of share capital [line items]
Beginning balance	€ 864	€ 806	€ 752
Ending balance	973	864	806
Share capital
Disclosure of classes of share capital [line items]
Beginning balance	3	3	3
Ending balance	3	3	3
Share premium
Disclosure of classes of share capital [line items]
Beginning balance	420	420	420
Ending balance	420	420	€ 420
Treasury shares
Disclosure of classes of share capital [line items]
Beginning balance	0
Ending balance	€ (10)	€ 0
Ordinary shares
Disclosure of classes of share capital [line items]
Beginning balance (in shares)	146,819,884
Ending balance (in shares)	146,819,884	146,819,884
Ordinary shares | Treasury shares
Disclosure of classes of share capital [line items]
Ending balance (in shares)	553,635

SHARE-BASED COMPENSATION - Narr

SHARE-BASED COMPENSATION - Narrative (Details) - EUR (€) € / shares in Units, € in Millions	6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023
Share Based Payment Plans [line items]
Number of instruments other equity instruments vested	1,338,744
Expense from share-based payment transactions with employees	€ 12	€ 10
PSUs
Share Based Payment Plans [line items]
Vesting period	3 years
Fair value at grant date (in euros) (in EUR per share)	€ 24.84
PSUs | Bottom of range
Share Based Payment Plans [line items]
Percentage of vesting multiplier	0%
PSUs | Top of range
Share Based Payment Plans [line items]
Percentage of vesting multiplier	20,000%
RSUs
Share Based Payment Plans [line items]
Vesting period	3 years
Number of instruments other equity instruments vested	473,952
Fair value at grant date (in euros) (in EUR per share)	€ 18.14
PSUs
Share Based Payment Plans [line items]
Percentage of vesting multiplier	100%
Number of instruments other equity instruments vested	864,792
Share price at grant date (in EUR per share)	€ 18.14

SHARE-BASED COMPENSATION - Inpu

SHARE-BASED COMPENSATION - Inputs to the Model Used for PSUs Granted (Details) - PSUs	6 Months Ended
	Jun. 30, 2024 € / shares
Disclosure of Input of Model Used for Performance-Based RSU [Line Items]
Fair value at grant date (in euros) (in EUR per share)	€ 24.84
Dividend yield	0%
Expected volatility	44%
Risk-free interest rate (US government bond yield)	4.46%
Share price at grant date (in EUR per share)	€ 18.14

SHARE-BASED COMPENSATION - Numb

SHARE-BASED COMPENSATION - Number and Movement of Potential Shares (Details)	6 Months Ended
	Jun. 30, 2024 shares
Disclosure of movement of potential shares [line items]
Potential Shares, Beginning balance (in shares)	3,461,549
Potential Shares, Granted (in shares)	1,145,745
Potential Shares, Over-performance (in shares)	297,335
Potential Shares, Vested (in shares)	(1,338,744)
Potential Shares, Forfeited (in shares)	(28,528)
Potential Shares, Ending balance (in shares)	3,537,357
PSUs
Disclosure of movement of potential shares [line items]
Potential Shares, Beginning balance (in shares)	1,797,179
Potential Shares, Granted (in shares)	600,268
Potential Shares, Over-performance (in shares)	297,335
Potential Shares, Vested (in shares)	(864,792)
Potential Shares, Forfeited (in shares)	(12,184)
Potential Shares, Ending balance (in shares)	1,817,806
Percentage of vesting multiplier	100%
Performance based shares forfeited upon non-fulfillment of performance conditions (in shares)	0
RSUs
Disclosure of movement of potential shares [line items]
Potential Shares, Beginning balance (in shares)	1,664,370
Potential Shares, Granted (in shares)	545,477
Potential Shares, Over-performance (in shares)	0
Potential Shares, Vested (in shares)	(473,952)
Potential Shares, Forfeited (in shares)	(16,344)
Potential Shares, Ending balance (in shares)	1,719,551

SUBSEQUENT EVENTS (Details)

SUBSEQUENT EVENTS (Details)		6 Months Ended		12 Months Ended
	Jul. 20, 2023	Jun. 30, 2024 EUR (€)	Jun. 30, 2023 EUR (€)	Dec. 31, 2023 EUR (€)	Jun. 30, 2024 USD ($)
Disclosure of non-adjusting events after reporting period [line items]
Proceeds from sale of subsidiary			€ 300,000
Redemption of senior notes		€ 4,000,000	€ 5,000,000	€ 53,000,000
Nominal value		1,888,000,000
Senior Unsecured Notes due 2026
Disclosure of non-adjusting events after reporting period [line items]
Nominal value		€ 234,000,000			$ 250,000,000
Nominal rate	5.875%	5.875%