| Document and Entity Information | Jul. 31, 2019 |
| Cover page. | |
| Document Type | 8-K |
| Document Period End Date | Jul. 31, 2019 |
| Entity Registrant Name | CRITEO S.A. |
| Entity Incorporation, State or Country Code | I0 |
| Entity File Number | 001-36153 |
| Entity Address, Address Line One | 32, rue Blanche |
| Entity Address, City or Town | Paris |
| Entity Address, Country | FR |
| Entity Address, Postal Zip Code | 75009 |
| Country Region | 33 |
| City Area Code | 14 |
| Local Phone Number | 040 2290 |
| Written Communications | false |
| Soliciting Material | false |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
| Entity Emerging Growth Company | false |
| Entity Central Index Key | 0001576427 |
| Amendment Flag | false |
