Renneval, a notorious elderly actor, is currently making time with the wife (Lana Marconi) of a ripe-for-cuckolding merchant named Henri (Bernard Blier). Having already been married twice to cheating spouses, Henri isn't psychologically prepared to find his third wife in the arms of Renneval. Fortunately, the aging actor is dressed as a clergyman (the part he's playing in his latest production), and thus is able to wriggle out of an uncomfortable situation by preaching an impromptu sermon about trust and fidelity!

Source : allmovie.com