Gerron first appeared on stage in a cabaret performance called
Kuka in Berlin. He joined the Wilden Buhne ("Wild Stage") cabaret troupe in 1921, subsequently working with several other troupes as well as working under theatre director
Max Reinhardt. in which he reprised
Mack the Knife, as well as compositions by
Martin Roman and other imprisoned musicians and artists. In 1944, Gerron was coerced into directing a
Nazi propaganda film intended to be viewed in "neutral" nations such as Switzerland, Sweden, and Ireland, for example, showing how "humane" conditions were at
Theresienstadt. The film had originally been planned in December 1943, but had been interrupted by a visit to Theresienstadt by a Red Cross delegation in June 1944. Ahead of the planned visit, the Nazis cleaned up the camp and deported large numbers of Jews to
Auschwitz concentration camp to avoid the appearance of overcrowding in the ghetto. The delegates were only allowed to speak to selected residents, under SS supervision, and the deception worked; the report stated that the city was "like any other", and the delegates did not investigate the thousands of Jews who passed through on their way to concentration camps. along with the film's entire performing entourage (except for Roman and guitarist
Coco Schumann). The next day, Reichsführer SS
Heinrich Himmler ordered the closure of the gas chambers. The film was completed in March 1945, and was never shown to the public. The lists that Gerron wrote and edited during the filming survived == Recognition ==