Income tax - Additional Information (Details) € in Thousands, $ in Millions |
12 Months Ended | |||
|---|---|---|---|---|
|
Dec. 31, 2025
EUR (€)
|
Dec. 31, 2024
EUR (€)
|
Dec. 31, 2024
USD ($)
|
Dec. 31, 2023
EUR (€)
|
|
| Disclosure of temporary difference, unused tax losses and unused tax credits [line items] | ||||
| Deferred tax asset | € 121,600 | € 110,900 | € 95,000 | |
| Unused tax losses | € 111,000 | 105,900 | 91,800 | |
| Deferred tax rate (percent) | 25.80% | |||
| Net loss for the period | € (23,961) | (68,132) | ||
| France | Unused Tax Losses | ||||
| Disclosure of temporary difference, unused tax losses and unused tax credits [line items] | ||||
| Deferred tax asset | 429,400 | 423,000 | € 367,000 | |
| France | Unused Tax Losses | Curadigm SAS | ||||
| Disclosure of temporary difference, unused tax losses and unused tax credits [line items] | ||||
| Deferred tax asset | € 4,900 | |||
| U.S. | Unused Tax Losses | ||||
| Disclosure of temporary difference, unused tax losses and unused tax credits [line items] | ||||
| Deferred tax asset | € 300 | $ 0.2 | ||