Clouseau's servant is Kato in the cast list of this movie, but Cato in the sequels.
All the crimes involve members of the Ballon household. "Ballon" is French for "balloon". And at one point Clouseau disguises himself as a balloon-seller.
This film was originally meant to have been an adaptation of the stage play by Harry Kurnitz. Walter Matthau and Peter Sellers were to have been the detectives, but Sellers did not like how things were going and wanted out. United Artists brought in Blake Edwards to keep Sellers on the project. Edwards looked at the script and thought that it might be better suited to the character of Inspector Jacques Clouseau, and rewrote the entire script with a young William Peter Blatty. It was released only three months after the original The Pink Panther (1963).
None of the characters in the Harry Kurnitz stage play appears in the film.
The role of Maria Gambrelli was originally given to Sophia Loren, but she became ill and couldn't do it. The next choice was Austrian actress 'Romy Schneider' , but she had a prior commitment.
First appearance of Kato (a.k.a. Cato) and Dreyfus in the Clouseau film series.
Only official Clouseau film not to use the name "Pink Panther" nor use that cartoon character in the opening credits.
The movie was completed before The Pink Panther (1963), but shelved because the studio didn't think it was any good. The success of the first film made the executives decide to release the shelved film. This also explains the short time span between the release of the first film and this one and the absence of Kato in the original but his appearance in this film and all the subsequent sequels. Burt Kwouk's character is named "Kato" (later "Cato") after the Asian sidekick in The Green Hornet (1940).
Two of the movie's gags originated by accident: -1. When Clouseau buzzes the intercom for "Miguel", then immediately corrects his own mistake: "Hercule!"
2. When Clouseau accuses Benjamin Ballon of killing Miguel "in a rit of fealous jage!" He obviously meant to say, "...fit of jealous rage." When Peter Sellers first botched these two lines, he was mortified and asked for a re-take. Yet both flubs got such giggles from the crew that director Blake Edwards decided to leave them in.
Premiere voted this movie as one of "The 50 Greatest Comedies Of All Time" in 2006.
In the scene where Clouseau rushes through a Paris apartment, only to go out the window -- into the Seine -- three cameras were set up to record the action. Of course a stunt double was employed, and told to "waggle" his legs on the way down, for more humour. The scene was filmed inside MGM's Stage 5 (in Boreham Wood, outside London) where a huge, 154,000 gallon tank, of tepid water, had been readied. Here, a set representing the first three stories of a French apartment house had been erected, right beside the tank. Because one cameraman had partly missed the fall the first time, the stuntman was asked to do it again. He changed out of his wet clothes, and duly did so, some minutes later. But the director felt he needed another, to be sure, and so a third take was done. Eventually only one camera angle was used, of course. The stunt man was paid about a hundred pounds for his part, it is believed.
According to the DVD Liner Notes of the film's first release (before the Pink Panther box set), the audience loved the Inspector Closeau cartoon that played over the credits so much that the entire preview audience applauded and gave the cartoon a standing ovation to which the theater had to stop the movie until everyone settled again.
According to Graham Stark, who plays Clouseau's assistant Hercule, in the scene where Clouseau gets his hand stuck in the globe and says "Look at that! I've got Africa all over my hand!", Peter Sellers ad-libbed the line. Also of note, the spinning globe gag is a re-hash of a gag from The Pink Panther (1963) where Clouseau did the same thing, except his hand slid off and he fell down.
In the scene where Clouseau and Hercule try to synchronize their watches before Clouseau goes into the Balon house, Peter Sellers and Graham Stark improvised the dialog.
According to Blake Edwards in the Box Set DVD Documentary, a week into filming, Sellers disappeared. When he returned, from an apparent holiday, Edwards was ready to kill him until Sellers told him of a peculiar hotel manager he met who had a funny French accent which Sellers was to give to the Clouseau character....Thus was born Clouseau's trademark mis-pronounciations such as "bimp" for bump and "miths" for moths.