Article L5422-15 of the French Labour Code
Any action or proceedings brought against an employer for failure to comply with the provisions of this Title, with the exception of Articles L. 5422-10, L. 5422-21, L. 5422-22 and L. 5422-24 and those of Chapter IV, shall be preceded by formal notice. The procedures for applying this article are determined by decree in the Conseil d’Etat.