With very few exceptions, all vocal performances heard during the movie were original recordings of the 1930's group. The old material was de-noised and digitally enhanced.
In this film, Heino Ferch and Ulrich Noethen play Jews who are persecuted by the Nazi Regime. In Downfall (2004), Ferch played Albert Speer and Noethen played Reichsführer-SS Heinrich Himmler.
Ben Becker and Meret Becker, who play lovers here, are brother and sister in real life. Otto Sander (1941-2013), who plays Bruno Levy, was the Becker siblings' real-life stepfather.
As correctly shown in the movie every member of the Comedian Harmonists had to pay penalty when coming too late. One minute being too late costed indeed 3 Reichsmark, 5 minute too late was 5 Reichsmarks. And as shown in the movie, Erwin Bootz was the most unpunctual member.
One of Bill Clinton's favorite films.