In her autobiography, Doris Day wrote that this was one of her least favorite movies, also citing The Ballad of Josie (1967), Caprice (1967), and Where Were You When the Lights Went Out? (1968). These were all movies to which her husband, Martin Melcher, had committed her without her consent.
Doris Day wrote in her 1975 autobiography that this was one of the movies that she did not want to do, but was forced to do because her husband and manager Martin Melcher had power of attorney and signed her for it without her knowledge or consent.
The interior set of the Von Trapp entry hall (featuring the split staircase) in The Sound of Music (1965) was re-used in this movie. The set was re-dressed for use as the hotel ballroom featured in the latter portion of this movie.
There is a neat in-joke in this movie. When the French children find out that Janet (Doris Day) is American, they ask her whether she knows Rock Hudson or Cary Grant. Day had previously co-starred with both of them. She worked with Hudson in Pillow Talk (1959), Lover Come Back (1961), and Send Me No Flowers (1964), and with Grant in That Touch of Mink (1962).
During filming, there were promotions, including a special trailer, for a "Doris (For a) Day Look-Alike Contest." The winner would get a trip to 20th Century Fox Studios in Los Angeles and appear in the film. While the winner, Tuula Mattila, got to meet and spend time with Doris Day, and appear in a promotional photo with her along with the runner-ups, she was given no role in the movie. It was just done as a publicity event.