When there is a contractual obligation, the fault is defined according to the organization of the relations desired by the parties and not according to the rules of tort. This so-called non-cumulative rule therefore reflects the primacy of the binding force of the contract. The principle dates from a judgment of the chamber of requests of the Court of Cassation of January 21, 1890. Contractual liability must come into play as soon as the damage is linked to the performance of the contract. (see for example Cass.civ. 2 June 9, 1993 ) It is not the same when the damage is not linked to the execution of the contract.
In the same way that article 1382 cannot be invoked in contractual relations, “the provisions of article 1384 al. 1 cannot be invoked in the event of a failure committed in the performance of an obligation resulting from a convention which cannot be disregarded in order to assess the responsibility engaged “( Civil Court 2 May 26, 1992)