The judgment of 4 October 2019 of the Court of Appeal of Liège is an opportunity to recall the principles of the formation of the (enterprise) contract and to give some advice.

The Court reminds us that:

“The contract of enterprise is a consensual contract which is not subject to any special form and which does not require, in order to be valid, to be evidenced in writing or to have been the subject of an estimate (A. Delvaux and D. Dessard, “Le contrat d’entreprise de construction”, Rép. not., tome IX, livre VIII, 1992, p. 119). »

In this case, the maître d’ouvrage and the contractor had not prepared a written estimate prior to the execution of the work. A statement had indeed been drawn up, but the Court considered that the maître d’ouvrage did not sufficiently prove that this statement made the law of the parties, as it was incomplete and unsigned. The Court therefore based itself on the amount invoiced at the end of the works and sentenced the contracting authority at that time.

The Court points out that the only way for the maître d’ouvrage to reduce the amount invoiced is to establish that the price is unjustifiable or abnormal.

This case highlights the nature of consensualism. A contract is consensual when it arises solo consensu, i.e. by the meeting of the consents of the parties. This exchange of will alone is sufficient to give rise to the convention, without any particular formalism being required.

In contrast to the consensual contract, there are real and solemn contracts.

The first are contracts that require, for their formation, the delivery of a thing (res) (example: the contract of deposit).

The latter must take a particular form. Take for example the donation, mortgage or marriage contract, which must be made by notarial deed. The termination of the commercial lease must also comply with the formalism of an authentic deed or a declaration before the judge in order to be valid.