Article 1317 of the French Civil Code
Among themselves, the joint and several debtors contribute to the debt only each for his or her share. He who has paid more than his share has recourse against the others in proportion to their own share. If one of them is insolvent, his share is divided, by contribution, between the solvent co-debtors, including the one who made the payment and the one who benefited from a solidarity remission.