Notes And Other Explanatory Information [Abstract]
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                                        2024-01-01 to 2024-12-31  | 
                            
                                
                                    
                                        2022-01-01 to 2022-12-31  | 
                            
                        
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| Notes and other explanatory information [abstract] | ||
| Disclosure of accounting judgements and estimates [text block] | 
                                        
                                             
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| Disclosure of auditors' remuneration [text block] | 
                                        
                                             
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| Disclosure of authorisation of financial statements [text block] | 
                                        
                                             
                                                Les comptes consolidés de l'exercice clos au 31 décembre 2024, d'une durée de 12 mois, reflètent la situation comptable de la société et de ses filiales (ci-après « le Groupe »). Ils ont été arrêtés par le Conseil d’Administration de la société du 25 avril 2025 qui en a autorisé la publication. Ces comptes seront soumis à l’approbation de la prochaine Assemblée Générale des actionnaires, le 19 juin 2025.
                                                
                                             
                                        
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| Disclosure of basis of preparation of financial statements [text block] | 
                                        
                                             
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| Disclosure of cash and cash equivalents [text block] | 
                                        
                                             
                                                (1) La trésorerie à la clôture se compose des 3 dernières lignes du tableau de flux de trésorerie.
                                                
                                             
                                        
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| Disclosure of cash flow statement [text block] | 
                                        
                                             
                                                Acquisition des immobilisations en flux de trésorerie
                                                
                                             
                                        
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| Disclosure of commitments [text block] | 
                                        
                                             
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| Disclosure of derivative financial instruments [text block] | 
                                        
                                             
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| Disclosure of discontinued operations [text block] | 
                                        
                                             
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| Disclosure of earnings per share [text block] | 
                                        
                                             
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| Disclosure of employee benefits [text block] | 
                                        
                                             
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| Disclosure of entity's operating segments [text block] | 
                                        
                                             
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| Disclosure of events after reporting period [text block] | 
                                        
                                             
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| Disclosure of expenses by nature [text block] | 
                                        
                                             
                                                6
                                                
                                             
                                        
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| Disclosure of fair value measurement [text block] | 
                                        
                                             
                                                9.5.2
                                                
                                             
                                        
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| Disclosure of finance income (cost) [text block] | 
                                        
                                             
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| Disclosure of financial risk management [text block] | 
                                        
                                             
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| Disclosure of general information about financial statements [text block] | 
                                        
                                             
                                                2
                                                
                                             
                                        
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| Disclosure of going concern [text block] | 
                                        
                                             
                                                Les comptes consolidés sont établis selon le principe de continuité d’exploitation
                                                
                                             
                                        
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| Disclosure of information about employees [text block] | 
                                        
                                             
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| Disclosure of information about key management personnel [text block] | 
                                        
                                             
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| Disclosure of intangible assets [text block] | 
                                        
                                             
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| Disclosure of inventories [text block] | 
                                        
                                             
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| Disclosure of joint ventures [text block] | 
                                        
                                             
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| Disclosure of liquidity risk [text block] | 
                                        
                                             
                                                9.1.3
                                                
                                             
                                        
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| Disclosure of market risk [text block] | 
                                        
                                             
                                                9.1.4
                                                
                                             
                                        
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| Disclosure of material accounting policy information [text block] | 
                                        
                                             
                                                2
                                                
                                             
                                        
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| Disclosure of other operating expense [text block] | 
                                        
                                             
                                                Des provisions constituées dans le cadre de litiges techniques ont été mises à jour en fonction des nouveaux éléments à disposition. Cette mise à jour conduit à la diminution du risque résiduel.
                                                
                                             
                                        
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| Disclosure of other operating income (expense) [text block] | 
                                        
                                             
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| Disclosure of other provisions, contingent liabilities and contingent assets [text block] | 
                                        
                                             
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| Disclosure of provisions [text block] | 
                                        
                                             
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| Disclosure of research and development expense [text block] | 
                                        
                                             
                                                7.2.1
                                                
                                             
                                        
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| Disclosure of revenue from contracts with customers [text block] | 
                                        
                                             
                                                Au sein de la division Bateau, les produits des activités ordinaires se répartissent comme suit selon les zones géographiques, les types de bateaux et les types de clientèle : 
                                                
                                             
                                        
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| Disclosure of share capital, reserves and other equity interest [text block] | 
                                        
                                             
                                                (1) Détail des autres variations - Normes IFRS 2, cf § 6.4
                                                
                                             
                                        
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| Disclosure of share-based payment arrangements [text block] | 
                                        
                                             
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| Disclosure of subsidiaries [text block] | 
                                        
                                             
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| Disclosure of trade and other payables [text block] | 
                                        
                                             
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| Disclosure of trade and other receivables [text block] | 
                                        
                                             
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