Hotel Paradiso (movie, 1966)

Monsieur Feydeau has writer's block, and he needs a new play. But he takes an opportunity to observe the upper class of 1900 Paris - Monsieur Boniface with a domineering wife, and the next-door neglectful husband Henri with a beautiful but ignored wife Marcelle. Henri traces architectural anomalies (most ghost sounds are drains), and plans a night at the Hotel Paradiso; but this hotel is the assignation spot of Marcelle and 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 under Feydeau's eye, and his play is the 'success fou' of the next season.