Where, under the law of a Member State, a taxpayer can choose between two causes of action in order to claim restitution of taxes levied contrary to Articles 49 TFEU and 63 TFEU and one of those causes of action benefits from a longer limitation period, the principles of effectiveness, legal certainty and the protection of legitimate expectations preclude legislation of that Member State, adopted after the claim has been brought, under which that longer limitation period is curtailed without notice and retrospectively. The answer to Question 1 is in no way affected by the fact that, when the companies belonging to the Aegis group lodged their claim using the cause of action which benefited from the longer limitation period, that cause of action had only been recognised (i) recently and (ii) by a lower court and (iii) was not definitively confirmed by the highest judicial authority until later.
AG CJ No C-362/12