Article 8a EEC

1. Every citizen of the Union shall have the right to move and reside freely within the territory of the Member States, subject to the limitations and conditions laid down in this Treaty and by the measures adopted to give it effect.

2. The Council may adopt provisions with a view to facilitating the exercise of the rights referred to in paragraph 1; save as otherwise provided in this Treaty, the Council shall act unanimously on a proposal from the Commission and after obtaining the assent of the European Parliament.