Cheating Couples (1980)

Elisabeth Buré plays the lead, as a sexually unadventurous wife whose husband (Richard Lemieuvre), with help from others, sets her up for some extramarital sex thrills and converts her into a sex-hungry exhibitionist. Serena takes center stage at the first cocktail party by bonking Gabriel Pontello on a glass coffee table in front of the guests, but Elisabeth one ups her in the final scene.