Article R2524-12 of the French Labour Code
Appeals to the Superior Court of Arbitration shall be made in writing and signed by the parties or a representative. The latter must provide proof of a special written power of attorney if he or she is not a lawyer at the Conseil d’Etat or the Cour de Cassation, or a lawyer duly registered at a bar. The application is sent to the president of the court by registered letter…