Article 27 TFEU

When drawing up its proposals with a view to achieving the objectives set out in Article 26, the Commission shall take into account the extent of the effort that certain economies showing differences in development will have to sustain for the establishment of the internal market and it may propose appropriate provisions.

If these provisions take the form of derogations, they must be of a temporary nature and must cause the least possible disturbance to the functioning of the internal market.