Nationale bestemmelser, hvorefter tjenesteydelser ikke behandles ens, uanset deres oprindelse, er kun forenelige med fællesskabsretten, hvis de kan henføres under en udtrykkelig undtagelsesbestemmelse som traktatens artikel 56.
National rules which are not applicable to services without discrimination as regards their origin are compatible with Community law only if they can be brought within the scope of an express exemption, such as that contained in Article 56 of the Treaty.