Erik Charell was around 35 years old when he gave "The Melody Makers" their new name "Comedian Harmonists" in 1928. But he is portrayed by a 57-year old actor.
In the movie the "Comedian Harmonists" are saying that they weren't performing after their last German concert anymore and the Jewish members left Germany soon after that. While the performing ban was set on 1st May 1934 they were still performing in foreign regions, like New York, Oslo etc. The Jewish members left Germany in the middle of 1935.
Robert Biberti and Erna Eggstein were never a couple. Erna was already married to Harry Frommermann in 1931, years before they left the country. Biberty had his first girlfriend Hilde in 1934 and married her in 1944.
Robert Biberti was a brunette, not a blonde, as shown in the movie.
The USS Saratoga is actually the USS Intrepid.
The same building is shown as an exterior establishing shot for both a hotel in Paris and an apartment building in Berlin.
During the performance on the USS Saratoga, black sailors are shown on the vessel mixed with white sailors. The navy did not integrate until 1949.
On the USS Saratoga, some naval officers shown are wearing Vietnam service medals.
Erwin Bootz didn't divorced is wife Ursula during the America tour. They only married in 1933 and divorced in 1938.
The song "In einem kühlen Grunde" was recorded in January 1932, while "Schöne Isabella aus Kastilien" was released in June 1932. In the movie however the band is shown recording the earlier song long after the later song was performed on stage.
When the Comedian harmonists hold their concert aboard the USS Saratoga, a parade of ships is seen, with the leading ship being an AEGIS class cruiser.
Roman Cykowski tells his future wife, Mary, that he is a religious Jew, yet he is often seen in the movie eating non-kosher food (such as the sauerbraten in Robert Biberti's house).
In the movie all contestants for Frommermann's group were waiting in line in the stairwell. In real life all the men had appointments and came on time. Robert Biberti also didn't sneak into the house as shown in the movie but had an appointment.