Towards a Court Mandated Harmonization of National Tax Rules Case 552/15, Commission v. Ireland

The CJEU's judgment in Commission v. Ireland is not just another case concerning a national system of vehicle registration taxes. It is true that the object of the dispute was Ireland's system of vehicle registration taxes and the way it was applied to vehicles leased in another Member State. The Court confirmed its earlier case law and considered the Irish system contrary to EU law because of a lack of proportionality. The court however went further, and expressly stated how the tax system should have been designed to be proportionate. This approach touches upon the exclusive competence of EU Member States in the designing of their national tax systems. Indeed, it raises the question whether the Court is simply protecting free movement rights or whether it is in fact harmonizing national tax systems through the application of its proportionality test.