Billy Wilder was drawn to Alexandre Breffort's stage farce by the challenge of depicting a man who is jealous of himself. Stripping away the songs that had been added for the Broadway musicalisation, Wilder and co-scenarist I.A.L. Diamond concocted a bawdy tale of smut and deceit, in which good intentions wind up being tainted by their environment. It proved to be Wilder's biggest hit of the 1960s, but he later conceded that it should have remained a play.
Wilder never forgave himself for breaking his golden rule of having Americans play foreigners with a native accent. However, he only had himself to blame as he rejected Brigitte Bardot's overtures to play the tart with the heart and, having fallen out with Marilyn Monroe and thought better of Elizabeth Taylor, he cast Shirley MacLaine in the title role for a reunion with Jack Lemmon, her co-star in The Apartment.
Unfortunatelty, the pair failed to recapture the chemistry they has generated in that infinitely more innocent study in sexual infatuation. This has much to do with the storyline itself, as Lemmon is forced to spend much of the action in disguise and he struggles to emulate the comic ease of Tony Curtis's caricaturisation of a millionaire in Some Like It Hot. Indeed, his reliance on movie gags for Lord X's mannerisms becomes an irritation and sits uneasily with the abrasive innuendo that comes to dominate Nestor and Irma's relationship.
Lemmon and MacLaine visited a Parisian hooker named Marguerite to prepare for their roles (and she reportedly kept slipping away to service her regulars), but the only sense of realism comes from Alexandre Trauner's typically atmospheric sets for Rue de Casanova and the Les Halles meat market (how subtle), where Nestor works to finance Lord X's nocturnal philanthropy.
Irma La Douce is a much better film that its reputation suggests. But its best joke lay in getting so much overt vulgarity past the Production Code censors.