A supply of services is effected "for consideration" within the meaning of Article 2(1) of the Sixth Council Directive (77/388) on the harmonization of the laws of the Member States relating to turnover taxes, and hence is taxable, only if there is a legal relationship between the provider of the service and the recipient pursuant to which there is reciprocal performance, the remuneration received by the provider of the service constituting the value actually given in return for the service supplied to the recipient.