v3.25.3
Significant events for the year ended December 31, 2024 and the nine-month period ended September 30, 2025 and subsequent events - For the year ended 2024 (Details)
€ / shares in Units, € in Thousands, $ in Thousands
1 Months Ended 3 Months Ended 7 Months Ended 8 Months Ended 9 Months Ended 27 Months Ended 31 Months Ended 142 Months Ended
Nov. 19, 2024
USD ($)
Jul. 11, 2024
shares
Jun. 21, 2024
EUR (€)
Apr. 04, 2024
shares
Mar. 28, 2024
EUR (€)
Jun. 30, 2024
EUR (€)
Mar. 31, 2024
shares
Sep. 30, 2025
EUR (€)
€ / shares
Sep. 30, 2024
EUR (€)
Aug. 31, 2025
plan
Sep. 30, 2024
shares
plan
Sep. 30, 2025
EUR (€)
shares
€ / shares
Sep. 30, 2024
EUR (€)
Nov. 30, 2019
EUR (€)
Jun. 30, 2016
EUR (€)
Sep. 30, 2025
EUR (€)
€ / shares
Nov. 19, 2024
shares
€ / shares
Aug. 20, 2023
EUR (€)
€ / shares
Dec. 16, 2013
EUR (€)
Disclosure of detailed information about borrowings [line items]                                      
Number of free shares plans issued | plan                   7 7                
Proceeds from borrowings                               € 175,000      
Par value per share (in euro per share) | € / shares               € 0.01       € 0.01       € 0.01 € 0.01    
Subsidies               € 20     € 4,140            
Number of ADS per Ordinary Shares | shares                                 1    
At-The-Market (ATM) Program                                      
Disclosure of detailed information about borrowings [line items]                                      
Expected proceeds from share issuance | $ $ 150,000                                    
Expected proceeds from share issuance, shelf registration | $ $ 350,000                                    
RNP-VIR conditional advance                                      
Disclosure of detailed information about borrowings [line items]                                      
Maximum drawdown capacity           € 6,300                          
Net proceeds from sale of royalty certificates                           € 4,032          
Proceeds from government grants                           € 1,123          
Repayment of excess conditional advances claimed           € 1,241                          
Percentage of conditional advances waived           60.00%                          
Conditional advances Bpifrance           € 2,945                          
Subsidies           1,872                          
CARENA conditional advance                                      
Disclosure of detailed information about borrowings [line items]                                      
Maximum drawdown capacity                                     € 3,840
Net proceeds from sale of royalty certificates           € 1,068                 € 2,187        
Percentage of conditional advances waived           60.00%                          
Conditional advances Bpifrance           € 3,255                          
Subsidies           € 2,251                          
Kreos & Claret financing, tranche B                                      
Disclosure of detailed information about borrowings [line items]                                      
Proceeds from borrowings         € 25,000                            
Kreos & Claret financing, tranche C                                      
Disclosure of detailed information about borrowings [line items]                                      
Proceeds from borrowings     € 25,000                                
Kreos & Claret Financing, Tranche B and C                                      
Disclosure of detailed information about borrowings [line items]                                      
Borrowings, maximum borrowing capacity                                   € 25,000  
Par value per share (in euro per share) | € / shares                                   € 1.00  
AGA-2024                                      
Disclosure of detailed information about borrowings [line items]                                      
Number of instruments issued (in shares) | shares                     1,946,125                
AGA-2024 | Tranche 1                                      
Disclosure of detailed information about borrowings [line items]                                      
Vesting percentage                     50.00%                
Vesting period                     2 years                
AGA-2024 | Tranche 2                                      
Disclosure of detailed information about borrowings [line items]                                      
Vesting percentage                     25.00%                
Vesting period                     3 years                
AGA-2024 | Tranche 3                                      
Disclosure of detailed information about borrowings [line items]                                      
Vesting percentage                     25.00%                
Vesting period                     4 years                
AGA-2024-6                                      
Disclosure of detailed information about borrowings [line items]                                      
Number of instruments issued (in shares) | shares   20,000                   0              
BSA-2024-1                                      
Disclosure of detailed information about borrowings [line items]                                      
Number of instruments issued (in shares) | shares       58,365     77,820         0              
Vesting percentage             25.00%                        
Vesting period             4 years