Ann-Margret got to keep whatever she wanted of the wardrobe created for her by Helen Rose as part of her contract to do the movie.
Despite its title, and being set mostly in Paris, this film was made entirely on the M-G-M studio backlot in Culver City, California.
The banks-of-the-Seine set where Ann-Margret and Louis Jourdan perform "Paris Lullaby" was recycled from elements of the set created for Gene Kelly and Leslie Caron's pas de deux to "Our Love is Here to Stay" in Un Américain à Paris (1951).
As pre-release publicity MGM sent costume designer Helen Rose to New York City and Chicago with "25 Fabulous Helen Rose Fashion Creations" from the $250,000 wardrobe designed for the film. The first fashion show was presented at the National Press Fashion Show sponsored by The New York Couture Group in January 1966. A week later the famous Pump Room in The Ambassador East Hotel was the scene for the Chicago show, followed by the world premiere of the film at The Chicago Theatre on January 28, 1966. A vial of the Robert Piguet fragrance "Bandit" was handed out to the ladies for the first three days of the movies run in Chicago.
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.