The Federal Constitutional Court has passed on several questions concerning the ECB's Public Sector Purchase Programme (PSPP) to the ECJ. As Helmut Siekmann explained in an interview with Börse.ARd.de, the judges in Luxembourg could decide that the Deutsche Bundesbank is no longer allowed to participate und in this case the German government would be obliged to take measures in order to stop the programme.
Boerse.ARD.de: EuGH soll EZB-Anleihenkäufe prüfen (only in German)