Article L2261-3 of the French Labour Code
Any representative trade union organisation of employees and any trade union organisation or association of employers or individual employers may join an agreement. However, if the activity in which they or their members engage does not fall within the scope of the agreement, their membership is subject to the provisions of articles L. 2261-5 or L. 2261-6, as applicable. Membership is notified to the signatories of the convention or agreement…