The authors believe that the judgment of the German Federal Constitutional Court contains serious breaches of EU law and is manifestly erroneous. The German judges refuse to apply the CJEU’s judgment and arrogate the power to assess the legality of European Central Bank (ECB) decisions and to review the reasoning of the CJEU, which they qualify as being ‘unintelligible and arbitrary’ for the sole purpose of declaring it ‘ultra vires’. They use the principle of proportionality in a legally incorrect way, ignoring the difference in scope between the latter and the principle of conferral. They make highly questionable use of the principle of democracy and of economic analysis to assess the merits of ECB decisions. A careful analysis of the judgment leads us to wish for the initiation of an infringement procedure.