v3.25.3
Intangible assets - Disclosure of reconciliation of intangible assets (Details) - EUR (€)
€ in Thousands
 9 Months Ended
Sep. 30, 2025
Sep. 30, 2024
Reconciliation of changes in intangible assets other than goodwill [abstract]    
Intangible assets other than goodwill at beginning of period € 6,606  
Intangible assets other than goodwill at end of period 6,606 € 6,607
LICENSES    
Reconciliation of changes in intangible assets other than goodwill [abstract]    
Intangible assets other than goodwill at beginning of period 75  
Intangible assets other than goodwill at end of period 75 75
SOFTWARE    
Reconciliation of changes in intangible assets other than goodwill [abstract]    
Intangible assets other than goodwill at beginning of period 3  
Intangible assets other than goodwill at end of period 2 3
PATENTS    
Reconciliation of changes in intangible assets other than goodwill [abstract]    
Intangible assets other than goodwill at beginning of period 6,529  
Intangible assets other than goodwill at end of period 6,529 6,529
GROSS VALUES    
Reconciliation of changes in intangible assets other than goodwill [abstract]    
Intangible assets other than goodwill at beginning of period 6,677 6,673
Acquisition 0 3
Disposal 0 0
Intangible assets other than goodwill at end of period 6,677 6,677
GROSS VALUES | LICENSES    
Reconciliation of changes in intangible assets other than goodwill [abstract]    
Intangible assets other than goodwill at beginning of period 120 120
Acquisition 0 0
Disposal 0 0
Intangible assets other than goodwill at end of period 120 120
GROSS VALUES | SOFTWARE    
Reconciliation of changes in intangible assets other than goodwill [abstract]    
Intangible assets other than goodwill at beginning of period 27 24
Acquisition 0 3
Disposal 0 0
Intangible assets other than goodwill at end of period 27 27
GROSS VALUES | PATENTS    
Reconciliation of changes in intangible assets other than goodwill [abstract]    
Intangible assets other than goodwill at beginning of period 6,529 6,529
Acquisition 0 0
Disposal 0 0
Intangible assets other than goodwill at end of period 6,529 6,529
AMORTIZATION    
Reconciliation of changes in intangible assets other than goodwill [abstract]    
Intangible assets other than goodwill at beginning of period (70) (70)
Increase (1) 0
Disposal 0 0
Intangible assets other than goodwill at end of period (71) (70)
AMORTIZATION | LICENSES    
Reconciliation of changes in intangible assets other than goodwill [abstract]    
Intangible assets other than goodwill at beginning of period (45) (45)
Increase 0 0
Disposal 0 0
Intangible assets other than goodwill at end of period (45) (45)
AMORTIZATION | SOFTWARE    
Reconciliation of changes in intangible assets other than goodwill [abstract]    
Intangible assets other than goodwill at beginning of period (25) (24)
Increase (1) 0
Disposal 0 0
Intangible assets other than goodwill at end of period (26) (25)
AMORTIZATION | PATENTS    
Reconciliation of changes in intangible assets other than goodwill [abstract]    
Intangible assets other than goodwill at beginning of period 0 0
Increase 0 0
Disposal 0 0
Intangible assets other than goodwill at end of period € 0 € 0