Article L. 420-1 of the Commercial Code prohibits agreements when their object or effect is to prevent, restrict or distort competition in a market. According to the Competition Authority, the classification of an agreement as restrictive of competition is not contingent on a specific and detailed description of the market concerned by the infringement.In effect, the agreement most often delineates the market. It is therefore sufficient that the sector in question is identified with sufficient precision to characterize the conduct observed and make it possible to attribute it to the operators who implemented it.

The market is defined as the place where the supply and demand of products or services considered to be substitutable meet. To determine the relevant market, the competition authorities carry out a multi-criteria analysis taking into account the nature of the product or service, its conditions of use and its marketing methods. The geographic market may cover the national territory or even a very small part of it.

The definition of the market may differ according to the type of control exercised by the competition authorities. While the analysis of the market in the context of merger control is prospective in nature, the analysis carried out for the same sector when examining anticompetitive practices is intended to provide an ex-post definition of the affected market.