Code of Organization and Civil Procedure (Cap. 12), article 396

396. In any action, it shall be lawful for the defendant to set up a counter-claim against the plaintiff, provided the claim of the defendant be connected with the claim of the plaintiff as stated hereunder: Grounds for reconvention. (a) if the claim of the defendant arises from the same fact or from the same contract or title giving rise to the claim of the plaintiff; or (b) if the object of the claim of the defendant is to set-off the debt claimed by the plaintiff, or to bar in any other manner the action of the plaintiff, or to preclude its effects. Effects of reconvention.