Komisario Palmun erehdys (Swedish title: Mysteriet Rygseck; international titles: Inspector Palmu's Mistake or Inspector Palmu's Error; US DVD title: The Rygseck Mystery) is a 1960 Finnish crime comedy film directed by Matti Kassila for Suomen Filmiteollisuus. It is set in 1930s Helsinki and centers on Inspector Palmu's investigation of the murder of rich and decadent Bruno Rygseck. It is based on Mika Waltari's 1940 novel of the same name, and was the first film adaptation of his Inspector Palmu novels.

The film was premiered on September 9, 1960, and at the time of its premiere, the film was already a great success with both audiences and critics. It has enjoyed great popularity over the years, and in 2012, it was voted the best Finnish film of all time by Finnish film critics, journalists and bloggers in a poll organized by Yle Uutiset. The film was also shown at the Tampere Film Festival in 1999.

The film was followed by three sequels, Gas, Inspector Palmu! (1961), The Stars Will Tell, Inspector Palmu (1962) and Vodka, Inspector Palmu (1969), which were produced by a different studio, Fennada-Filmi, but directed by Kassila and featured the same core cast.