Article 60 EWG

Services within the meaning of this Treaty shall be deemed to be services normally supplied for remuneration, to the extent that they are not governed by the provisions relating to the free movement of goods, capital and persons.

Services shall include in particular:

(a) activities of an industrial character;
(b) activities of a commercial character;
(c) artisan activities; and
(d) activities of the liberal professions.

Without prejudice to the provisions of the Chapter relating to the right of establishment, a person supplying a service may, in order to carry out that service, temporarily exercise his activity in the State where the service is supplied, under the same conditions as are imposed by that State on its own nationals.