Adolf Hitler reportedly planned to execute the makers of this film upon winning the war.
A libel suit for $75,000 was filed on Monday, July 3, 1939 in U.S. Federal Court against Warner Bros. by Katherine Moog, in which she claimed that the picture "Confessions of a Nazi Spy" and its advertisements defamed her character. Plaintiff alleged that Warners, without her consent, used her name to exploit the picture and connected her with the character "Erika Wolf," played by Lya Lys.
According to the article "Hollywood Goes to War" by Colin Shindler in the film history tome "The Movie", "Warner Brothers, who had made the one explicitly anti-Nazi film of the US pre-war period (1939, "Confessions of a Nazi Spy" were unofficially told by the US government not to make any more such pictures. In April 1940 the news filtered back to Hollywood that several Polish exhibitors who had shown "Confessions of a Nazi Spy" had been hanged in the foyers of their own cinemas."
According to the book "The Films of World War II" by Joe Morella, Edward Z. Epstein and John Griggs, "While this Warner Bros. film was not as sensational as its advance publicity led audiences of the day to expect, it was, nevertheless, the first out-and-out anti-Nazi film from a major American studio . . . it made its point by sticking closely to the facts of a real-life spy trial which had involved high officials in the German Third Reich as well as their American operatives . . . This film was instrumental in bringing about the 'Hollywood war-mongering' charges. Actors and producers received murder threats. American-based German officials screamed 'conspiracy!' and the film was subsequently banned by countries who feared offending Germany. In the United States, however, it was a popular success, prompting other studios to hurry production of more anti-Hitler films."
On Manday, July 3, 1939, Warner's legal department advised company's theaters that "Confessions of a Nazi Spy" must not be publicized as "based on the book written by Leon G. Turrou."
Some well-known actors (including Anna Sten and Marlene Dietrich) refused to be in the movie fearing reprisals against relatives living in Europe. Many who did appear changed their names for the same reason, accounting for large number of aka's in the cast list.
The film did record-breaking box office business around the world despite being banned in Germany, Japan and 18 Latin American countries.
The movie is based on an actual spy-ring trial in New York in 1938, which convicted four individuals of spying for the German government.
This was the first anti-Nazi movie made in Hollywood before the start of World War II.
This was the first major Hollywood film with the word "Nazi" in the title (though it appears Inside Nazi Germany was actually the first, this was a short and not a major feature). A number of American movies and documentaries in the 1940s would follow with the word "Nazi" in their title, among them Nazi Agent ; The Nazis Strike; The Story of One of Hitlers Children as Adapted from: Education for Death - The Making of the Nazi (USA) See: Education for Death; Nazi Concentration Camps; Nazi Spy Ring (aka The Dawn Express); and The Nazi Plan. A number of these titles mentioned were also spy melodramas.
Warner Bros. increased security throughout the production and some actors slept on the Warners lot. Sabotage was suspected when a boom holding one of the cameras collapsed, narrowly missing director Anatole Litvak.
When this movie was made, America was not part of World War II. At this time a number of Hollywood studios were pro-American involvement in the war. This movie is one of a number of films made during the late 1930s and early 1940s that represented pro-American intervention in the war, including such films as A Yank in the R.A.F., Man Hunt, Foreign Correspondent, The Mortal Storm, and Sergeant York.