La comtesse Ixe (1976)

A group of friends come together to have a party, but in the woods near the castle a kleptomaniac is hiding and waiting to take advance of the partygoers. She introduces herself as countess Ixe a lady that nobody knows but with a legendary life because she often dances naked in front of her guests. The thief however wants to go a bit further and poisons the champagne with an aphrodisiac so that in no time all partygoers are deeply involved in a big orgy. Meanwhile the real countess Ixe arrives on the scene...