M-G-M apparently offered Ann-Margret's role to Doris Day, who was then America's #1 box office draw. Day, who would have given a decidedly different performance, wisely turned it down because she had issues with the script.
Paris the den of all evil.
Maggie Scott: Well, it's true isn't it? Everybody thinks so.
Marc Fontaine: Not everybody, you do. Miss Scott. There is no safer city in the world than Paris, if you want it that way. I'm sorry to disappoint you; but, the wild Paris by night died 50 ...