Benoit and Dassonville claimed that their prosecution for selling Scotch whisky without a certificate was contrary to the TEEC article 30 (now TFEU art 34).

In response, they challenged the legality of the certificate law, based on the rule in article 30 that there should be no quantitative restrictions on trade, or measures of equivalent effect.

The Belgian authorities, the Procureur du Roi contended that because the purpose was to protect consumers, not regulate trade, the measure fell outside TEEC article 30.

In the absence of a Community system guaranteeing for consumers the authenticity of a product’s designation of origin, if a Member State takes measures to prevent unfair practices in this connection, it is however subject to the condition that these measures should be reasonable and that the means of proof required should not act as a hindrance to trade between Member States and should, in consequence, be accessible to all Community nationals.

That may be the case with formalities, required by a Member State for the purpose of proving the origin of a product, which only direct importers are really in a position to satisfy without facing serious difficulties.

Consequently, the requirement by a Member State of a certificate of authenticity which is less easily obtainable by importers of an authentic product which has been put into free circulation in a regular manner in another Member State than by importers of the same product coming directly from the country of origin constitutes a measure having an effect equivalent to a quantitative restriction as prohibited by the Treaty.

More particularly, an exclusive dealing agreement may adversely affect trade between member states and can have the effect of hindering competition if the concessionaire is able to prevent parallel imports from other member states into the territory covered by the concession by means of the combined effects of the agreement and a national law requiring the exclusive use of a certain means of proof of authenticity.