A married woman arranges an adulterous liaison at a sleazy hotel, but her plans are thrown into disarray by the unscheduled arrival of her husband. Romantic comedy, with Gina Lollobrigida, Alec Guinness and Robert Morley.

Monsieur Feydeau has writer's block and he needs a new play, so he takes an opportunity to observe his upper class neighbors of 1900 Paris. There is Monsieur Boniface with hard domineering wife Angelique; also, Monsieur Cotte with beautiful but neglected wife Marcelle. Henri Cotte traces architectural anomalies (mostly "ghost" sounds in the drain pipes) and plans a night at the Hotel Paradiso, which happens to be the chosen romantic rendezvous spot of Marcelle and Monsieur Boniface. One wife, two husbands, a nephew, and the perky Boniface maid, all at this 'by the hour' hotel and consummation of the affair is, to say the least, severely compromised (not the least by a police raid). All of this is under Feydeau's eye, and his play is the 'success fou' of the next season.