The voice of the man in the tweed jacket who interrogates Michelle in her apartment is dubbed by Roman Polanski.
Director Cameo: [Roman Polanski] the taxi driver who hands over the matches to Dr. Walker.
Harrison Ford thought that "Frantic" was a misleading title for the film as the script didn't have a frantic pace. He suggested that "Moderately Disturbed" would be a more appropriate title. Polanski wasn't amused.
Due to studio pressure, 15 minutes were trimmed from the original running time and a new ending was shot.