- Hostility on the Set: Marlene Dietrich reportedly didn't think too highly of her co-stars, calling John Lund "that piece of petrified wood" and referring to Jean Arthur as "that ugly, ugly woman with that terrible American twang."
- Mirroring the triangle in the plot of the movie, Arthur and Dietrich vied with each other for Billy Wilder's attentions, with Dietrich usually coming out far ahead. Although this was their first picture together, the two Europeans were old friends, and they would frequently be off in a corner of the set, talking in German and giggling. Sometimes Wilder went to Dietrich's dressing room for lunch or tea. All of this had Arthur seething, compounded by the fact that she was always insecure about her looks and knew she was playing the Plain Jane to Dietrich's Glamour Girl in this film. Reportedly, she showed up at his house one night with her husband, producer Frank Ross, visibly shaken and eyes red from weeping. She demanded to know what he had done with a certain close-up of her, "the one where I looked so beautiful," and accused Dietrich of having forced Wilder to burn it. One story claimed he eased her concern by showing her the close-up, but Wilder always said no such shot ever existed. Truth of the matter was, Arthur, although only a year and a half older than Dietrich (though neither of them were admitting their right age at the time), could not hide her age from the all seeing eye of the close-up camera, even with the help of false eyelashes and soft focus, and photographed from her traditionally favored left three-quarters.
- No Stunt Double: For the scene in which Phoebe gets drunk and ends up being tossed in the air by rowdy soldiers, Billy Wilder wanted to use a double, but Jean Arthur insisted on doing it herself. After the physically strenuous take, she said loudly and pointedly, "What will you require next from me, Mr. Wilder," to a round of sympathetic applause from the crew.
- Working Title: Operation Candy Bar and Foreign Affairs. Billy Wilder and Charles Brackett preferred the former.
Trivia / A Foreign Affair