Fickfreunde in Paris (1978)

Two characters, Lemieuvre and Royer, arrive in a city and inquire about a hotel from a sex worker. She leads them to her room, where they unexpectedly join a sexual encounter with her and her pimp, Cyril Val.

Val then takes them to a large house, specifically to Cathy Stewart's bedroom. Mistakenly thinking Royer is her boyfriend, Stewart engages in sexual activity with him while Lemieuvre hides. He is later discovered, resulting in another threesome involving a simulated act.

Subsequently, the two friends travel to a ski resort and mistakenly enter the wrong chalet. The rightful occupants, Diane Dubois and Liliane Lemieuvre, return, and they all decide to share the double bed, leading to further sexual activities. They eventually return to the city and Val's house, where a larger group sexual encounter occurs. Alban Ceray arrives, intending to arrest Lemieuvre and Royer, but is distracted by Diane and Liliane, resulting in an even larger gathering of participants in the orgy.

The film is titled "Cuisses en délire" and is noted as a companion piece to "Bouches expertes."