Recent Court of Justice of the European Union (CJEU) and European Court of Human Rights (ECtHR) judgments imply that some form of ‘European Intervention’ providing for a coordinated approach towards the determination, and quantification of tax penalties has become necessary. Disproportionate tax penalties and concurrent penalties pose a serious hurdle to achieving the European Commission’s political mission to put a tax system in place ‘where everybody pays their fair share’ of taxation. Given current judicial trends, the situation calls for the creation of an ad hoc taxpayers’ charter which imposes red lines for tax penalty regimes. Matters such as ultra duplum, minimus vitalis, non bis in idem, ceiling rates for cumulative penalties and the coordination of punitive measures call for an element of harmonization.