Even though Vincente Minnelli is credited as the sole director, he was sometimes tied up with his divorce from Judy Garland and other directing projects, leaving Gene Kelly to take over the directing duties.
Leslie Caron didn't speak English when she landed her first major role. She had a vague understanding of the language due to having an American mother, but was not conversant. Luckily for her, the part didn't have many lines and was comprised of mostly dancing, a skill that Caron was very fluent in.
According to Leslie Caron, her introductory dance sequence, which included a seductive dance with a chair, was considered too suggestive by some censors. Gene Kelly directed the brief fantasy dance sequences shown as Lise is introduced.
Arthur Freed originally just wanted to buy the rights to the George Gershwin number "American in Paris," but Ira Gershwin made the condition that he'd only sell on the condition that if a musical were to use the song, it would use only Gershwin numbers as its other songs.
The ballet sequence was almost cut because the shooting was behind schedule, but MGM studio head Louis B. Mayer stood by Arthur Freed, Vincente Minnelli and Gene Kelly in withholding the release of the movie because he felt the movie wouldn't be effective without it.
Despite the objections of Gene Kelly who wanted to shoot on location in Paris, the movie was shot at MGM Studios in California, on 44 sets built for the film. It was reportedly difficult for the studio to secure travel arrangements or locations for shooting. Two shots in the picture are from Paris, but they don't involve Kelly.
Oscar Levant's dream sequence may be a tribute to Buster Keaton. In the opening sequence of The Play House (1921), Keaton also played every role - conductor, every member of the orchestra, stage hand, all nine actors on stage, and each member of the audience.
Irene Sharaff designed a style for each of the ballet sequence sets, reflecting various French impressionist painters: Raoul Dufy (the Place de la Concorde), Edouard Manet (the flower market), Maurice Utrillo (a Paris street), Henri Rousseau (the fair), Vincent van Gogh (the Place de l'Opera), and Henri de Toulouse-Lautrec (the Moulin Rouge). The backgrounds took six weeks to build, with 30 painters working nonstop.
The film's most famous sequence - the climactic ballet - was not conceived until midway through production and was largely brought about due to Nina Foch's unavailability (the actress was out of the film for three days due to contracting chicken pox). Alan Jay Lerner came up with the idea for the ballet, and wrote it, in those three days.
A scene in which Gene Kelly dances and sings "I've Got a Crush on You" while in his pajamas was filmed but did not make final cut. Kelly created a similar number with the song "All I Do Is Dream of You" for his next movie musical, Singin' in the Rain (1952), and it also ended up on the cutting room floor.
After Arthur Freed and Ira Gershwin reached an agreement during their weekly pool game, film rights to George Gershwin's "An American in Paris - A Tone Poem for Orchestra" were purchased for $158,750, and Ira received $56,250 as a consultant to write any necessary new lyrics for songs used.
There was a break in production after 1 November 1950, at which point Gene Kelly began rehearsing the ballet choreography. By the time production for that final sequence resumed on 6 December, Vincente Minnelli had finished directing another film - Father's Little Dividend (1951).
Producer Arthur Freed wanted Marge Champion to star in this movie, but at the time Champion didn't want to break up her dance act with her husband Gower Champion. So she persuaded Freed that he should cast a French girl in the role instead.
The song "Showcase to Paradise" is the only one in the film that is presented as a show tune; the rest are all seamlessly integrated into the action. In the segment, Georges Guétary walks up a staircase adorned with showgirls whilst singing the number. Gene Kelly later said that probably the hardest thing he had to do in the film was teach Guetary how to climb steps while performing without tripping up. Another factor complicating the shooting of this sequence was the intensity of the studio lights which proved too hot for several of the showgirls who passed out.
On the two-disc special edition DVD released in 2008 by Warner Home Video, footage of one musical scene has been restored as a bonus: Georges Guétary, accompanied by Oscar Levant at the piano, singing "Love Walked In" to Leslie Caron in a café. Audio extras include Gene Kelly crooning "I've Got a Crush on You," plus two versions of "But Not for Me": a Georges Guétary vocal and an Oscar Levant piano solo.
Oscar Levant and Gene Kelly both grew up in Pittsburgh. Kelly appeared in a Cap and Gown show at the University of Pittsburgh whose music was written by Oscar's talented musical brother, Benjamin, who went on to become a urologist.