Originally intended to be a vehicle for William Powell and Myrna Loy, Rosalind Russell was brought in as Loy was "on strike" for better pay after the huge success of The Thin Man (1934).
Apparently, in a less than courageous move, the sound track has the references to the spies being German are edited out, to not offend Adolf Hitler's Germany, it would seem. It is done in a primitive, ham-handed way, such as the word "German" scratched out of sentences, with a noise that sounds like damage to the film itself, and a patch of Powell's dialogue is replaced with a bizarre voice-over that sounds nothing like him, as if he were "possessed" for a few seconds.
The studio was not happy with the ending and, taking in responses from preview audiences, ordered reshoots a month after original filming had ended. Sam Wood took over as director and James Wong Howe as cinematographer for the reshoots but received no on-screen credit for their three weeks of work. Seventeen new sets had to be constructed for this second round of filming in September of 1935.
Based on the 1931 book "The American Black Chamber", by Herbert O. Yardley, a cryptoanalyst for the U.S. Cipher Bureau, also known as The Black Chamber. This forerunner of the National Security Agency was formed after WWI in 1919 and was disbanded in 1929 when the State Department and the U.S. Army withdrew funding for the organization. Yardley then was out of a job and, needing money, wrote the book.
It was typical of the major studios during the 1930s to avoid offending Adolf Hitler's Third Reich, to avoid any negative affect on foreign sales. (In this case, direct mention of Germany was edited out.) A notable exception was Warner Bros., whose representatives had been assaulted in Berlin by Nazi thugs.