Jewish groups in Germany are still enraged at Roger Waters after images from his Berlin concert showed him dressed in apparent Nazi colors and satirically imitated firing a machine gun into the crowd. Multiple groups held a demonstration outside a venue in Frankfurt, Germany, on Sunday to protest the city allowing him to play at the Festhalle, where thousands of Jews were once beaten by Nazis—something Waters fought in court to secure after a lawsuit was filed. “Against this historical background, the concert should not have taken place under any circumstances,” Sacha Stawski, one of the protest organizers as the head of the group Honestly Concerned, told the Associated Press. Berlin police have since opened an investigation into Waters for incitement, while Waters has denounced any suggestion that he is antisemitic.