R.L. Aldewereld v. Staatssecretaris van Financiën, Case C-60/93, CJEU, 12 June 1994

Application of the legislation on the free movement of workers to the worker who carries out his activity in another Member State. Prohibition of double taxation. 

Regulation (EU) n. 492/2011 on the right to free movement of EU workers within the EU.

The rules aimed at ensuring the free movement of workers within the territory of the Union and in particular the rules concerning the determination of the national legislation to be applied, contained in Regulation no. 1408/71, prevent a worker residing in the territory of a Member State employed by a company established in another Member State and who carries out his activity exclusively outside the territory of the Union and is subject to the payment of contributions under the legislation of the other Member State, the payment of social security contributions is required by the legislation of the Member State in which he resides. Indeed, the mere fact that a worker's services are performed outside the territory of the Community is not sufficient to disapply the Community rules on the free movement of workers if the work maintains a sufficiently close connection with the territory of the Community.