Continuity mistake: In the opening sequence, Felix (Jack Lemmon) goes into the Metropole Cafe. One of the people he passes as he enters is a young woman with a thin face and very distinctive nose and eyes. He goes in, has a drink, hurts his neck, and leaves. As he is leaving, the camera pans the band and go-go dancers. One of the dancers is the young woman who had just left as he was entering.
Continuity mistake: When Thorndyke and Havershaw are working in the garage towards the end of the movie, Thorndyke says to Havershaw "You're despicable!" and squirts oil on him. At this point, you can see the top of Havershaw's overalls is covered in oil, but when Thorndyke squirts oil at him a few shots later, the oil has disappeared.