Merle Oberon was married to the cinematographer of the film, Oklahoma-born Lucien Ballard, at the time "Berlin Express" was made.
Reinhold Schünzel, who plays Professor Walther in the film, was the director of the original 1933 German stage comedy Viktor und Viktoria, which Blake Edwards later adapted as Victor/Victoria, a vehicle for his wife Julie Andrews. Reinhold also appeared in the original Georg Wilhelm Pabst film of L'opéra de quat'sous with 'Lotte Lenya'.
The first Hollywood production in Germany after World War II.