It is sufficient that an appreciable change is capable of being caused in the pattern of trade between Member States. Nevertheless, in many cases involving a single Member State the nature of the alleged infringement, and in particular, its propensity to foreclose the national market, provides a good indication of the capacity of the agreement or practice to affect trade between Member States.
Néanmoins, dans de nombreux cas impliquant un seul État membre; la nature de l'infraction alléguée, et notamment sa propension à interdire l'accès au marché national, renseigne bien sur la capacité de l'accord ou de la pratique d'affecter le commerce entre États membres.