La Puce à l'oreille(1996)

Raymonde Chandebise suspects her husband Victor-Emmanuel of cheating on her. Her best friend advises her to find out for sure and to use a stratagem. Both of them send him a false letter, written by a beautiful stranger, giving him an appointment at the "Minet Galant"! But they are completely unaware that the hotel's waiter, a simpleton, is a look-alike of poor Victor-Emmanuel!