Peek Freak (1987)

Siegried Cellier and Jean-Louis Vattier live in an apartment opposite a pavement café where Dawn Cumming, who lives in an apartment above the café, picks up men (and women) for sex. Siegried and Jean-Louis spy on her activities and photograph them while getting off themselves. Eventually communication is established by phone, Dawn plays up to the camera and the two photographers direct a female her way. Then they meet for a swinging session and finally Siegried and Dawn swap places, Siegried donning a dark wig and taking on three men in Dawn’s apartment with Jean-Louis unwittingly looking on, until Dawn turns up and sucks him off while he watches what he now knows to be his wife.