Capucine plays a character named Renée Lefébvre. Capucine's birth name is Germaine Lefébvre.
Richard Burton appears in a cameo with Peter O'Toole in a scene in a bar where Burton asks O'Toole "Don't you know me from someplace?" and O'Toole responds "Give my regards to what's her name." The dialogue is a reference to their appearance together in Becket and to Burton's wife at the time, Elizabeth Taylor. Screenwriter Woody Allen later said of the Burton cameo, "It was so cute, you want to vomit."
Woody Allen's feature film debut.
Dr. Fassbender's line about Rita "knowing James Bond" was ad-libbed by Peter Sellers, which explains why Ursula Andress laughs out loud afterwards. Andress played Honey Ryder in the first James Bond film, Dr. No.
The art nouveau house featured in the movie was designed by the same architect, Hector Guimard, who designed the famous Paris Metro stations. It was demolished four years after the movie was made.
The movie began as a semi-autobiographical project for Warren Beatty with Woody Allen writing the screenplay. Eventually Beatty's role became smaller than originally intended and producer Charles Feldman ignored his request to cast his then-girlfriend Leslie Caron instead of Capucine. Beatty then left the project and his role was taken by Peter O'Toole.
The scene where Woody Allen's character celebrates his birthday on the wharf was filmed on December 1, 1964 - Woody's 29th birthday.
The title is a line Warren Beatty used on his girlfriends at the time.
While rehearsing his lines about people cheating on each other in the hotel, French actor Jacques Balutin suddenly saw Peter O'Toole unexpectedly roar with laughter. Asking Peter Sellers to join them, O'Toole insisted that he did it one more time. Obliging to his request, his performance produced the same hysterical effect. Only when both actors stopped laughing out loud did they admit to Balutin his bad pronunciation of "cheat on" made it sound more like "sh*t on".