Stanislas Dubois is a businessman who dresses according to contemporary standards. When he meets a woman on a date in a restaurant, he's clad in a coat. Upon leaving he confuses a similar coat with his own one. Following this mix-up he becomes increasingly aware that he's got meanwhile something about him which attracts peculiar people. Hidden in his new coat is a microfilm which interests more than one secret service. Once he's already drawn into the world of international espionage, a secret service of his own country hires him to lure enemy spies into a trap, hereby serving as bait.

Source : Wikipedia