Cary Grant had announced his retirement from acting in February 1953, stating that since the rise of Method actors like Marlon Brando, most people were no longer interested in seeing him. He was also angry at the way Charles Chaplin had been treated by the HUAAC. He was lured out of his retirement to make this film, and thereafter continued acting for a further 11 years.
According to Paramount production files contained at the AMPAS Library, Alec Coppel worked on the script for about a week in mid-November 1954, shortly before the final set of retakes was done.
According to the script, the character John Robie was 35. Cary Grant was 50 at the time of filming.
For the scene between Robie and the insurance agent, when they talk about the cook's sensitive hands, the German version of the movie differs completely from the original. In English, Robie notes she once strangled a German general without a sound, while in German, he says she once caught a lion escaped from a circus with her bare hands.
Francie (Grace Kelly)'s car is a Sunbeam-Talbot Alpine Sports Mk I roadster.
French actor Charles Vanel (as Bertani) could not speak a word of English. All his lines were dubbed.
In an early shot, a newspaper article called "Europe's Lighter Side" by Art Buchwald speculates on whether "the Cat" is on the prowl again. Buchwald actually wrote a column by that title for the New York Herald Tribune's European edition early in his career. He left school and moved to Paris in 1948, seven years before this film was released.
In the scene on the float platform, Danielle makes a point of how much younger she is than Frances. In fact, Brigitte Auber (b. April 1928) was a year and a half older than Grace Kelly (b. November 1929).
In this film Jessie Royce Landis plays Cary Grant's potential mother-in-law. In North by Northwest, she would play his actual mother.
John Robie mentions that as a youth he was in a trapeze group that traveled around Europe. In real life, Cary Grant was in an acrobatic troupe that toured around Europe (and eventually came to America) when he was young.
On 14 September 1982, Grace Kelly was killed in an automobile accident in Monaco, supposedly on the very same road as her famous chase scene in this film and not far from where she had a picnic scene with Cary Grant. She was 52 years old and lost control of her car after apparently suffering a stroke while at the wheel.
The boat that Danielle (Brigitte Auber) and John (Cary Grant) travel in early in the film is named the "Maquis Mouse": a play on Maquis (the French underground) and Mickey Mouse.
The filming of this movie on the French Riviera plays a pivotal role in Wu Ming's novel "54". The action takes place in the springtime of 1954, and nearly all the characters in the novel (including Cary Grant, an Italian American mafioso nicknamed "Steve Cement", and two Parisian gangsters from Du rififi chez les hommes) cross each other's path in Cannes and Nice.
The movie was filmed in the summer of 1954 but its release was delayed because the producers felt the age difference between Cary Grant and Grace Kelly was too great for their romance to be believable. Ironically, when released in 1955 the film immediately became one of the biggest hits of the decade.
The picnic scene in which Francie (Grace Kelly) asks John (Cary Grant), "Do you want a leg or a breast?" as well as John's response, "You make the choice." was an improvisation.
The two leads ranked #8 on Moviefone's 'The Top 25 Sexiest Movie Couples'. May 2008
There are subliminal shots of a black cat the first few times that John Robie (Cary Grant) appears. John's nickname is "the cat" because of his stealth ability.
There is a second reference to 'Alfred Hitchchock (I)''s dislike of eggs. A raw egg is thrown hitting the glass and splattering in the restaurant at the beginning when the kitchen staff believe Cary Grant is responsible for the recent thefts. He is also offered a saucer of milk referring to "cats".