Brussels has launched a legal case against Germany over an alleged breach of “the principle of the primacy of EU law” by the country’s constitutional court. The “infringement proceeding” is the result of a ruling last year by the German federal constitutional court in Karlsruhe which it is claimed undermined the pre-eminence of the European court of justice (ECJ). The German court had contradicted the ECJ by instructing Berlin to delay approval of a European Central Bank multi-trillion-euro bond-buying programme due to concerns that it was straying into financing member states, something it claimed was not permitted under EU founding treaties. The constitutional court later ruled that the bond-buying could proceed, but in a statement on Wednesday the European Commission said the initial decision set “a dangerous precedent for [European] Union law, both for the practice of the German constitutional court itself, and for the supreme and constitutional courts and tribunals of other member states”. “The German court deprived a judgment of the European court of justice of its legal effect in Germany, breaching the principle of the primacy of EU law,” a commission spokesperson said. The German government now has two months to respond to a letter from the commission over the case, which could ultimately lead to hefty fines being issued by the ECJ in Luxembourg. The commission spokesperson said: “It is for the member state to identify possible solutions. Any solution must be in line with EU law and respect the principle of the primacy of EU law.” The core of the dispute is the German constitutional court’s 2020 ruling that the European Central Bank’s bond-buying programme could be illegal unless it was proven that each of the purchases were necessary. It was also claimed by the court that the ECJ had acted ultra vires (beyond its powers) by approving the bond-buying. The ECJ had responded strongly at the time by issuing a statement stating that it “alone” had “jurisdiction to rule that an act of an EU institution is contrary to EU law”. That response was a reflection the growing concerns in Brussels over the fragmentation of the EU’s legal order. The commission’s letter of notice to the German government in turn highlights anxiety in Brussels that the behaviour of the Karlsruhe court could encourage those in Poland and Hungary to act in similar ways. “This could threaten the integrity of [EU] law and could open the way to a ‘Europe à la carte’,” a commission spokesperson said. “The last word on EU law is always spoken in Luxembourg.” The ECJ has also made a series of rulings on Polish laws which have pitted it against Warsaw. In 2019, the EU’s highest court said Poland had broken the law when it sought to lower the retirement age for judges. The ECJ found that a 2017 policy to lower the retirement age for ordinary judges in Poland was unlawful because it gave too much power to the executive, and that a decision to compel female judges to retire five years earlier than men broke EU equality law. Both Poland and Hungary are also currently subject to article 7 investigations over claims they have undermined the rule of law, a process that could theoretically lead the countries to lose voting rights in the EU’s institutions.