While hanging out, he and his various friends and acquaintances sunbathe and swim in the nude, though one character admits it's technically illegal, and there is apparently a more 'family-friendly' beach on the other side of the lake where one man says you can meet women. Being a French (European) film, there is copious amounts of full-frontal male nudity, but it's handled within the context of the story: young gay man hangs out at a beach on a mountain lake - a well-known (in the stort) hangout and cruising spot for gay men - I'm assuming it's also a public park - where he meets a handsome stranger who may or may not be a murderer.
While I was indifferent to the explicit sex and nudity, and for all its hype, this is not porn: there is no actual anal penetration shown (though admittedly if the actors were actually engaged in real sex, it's still shot like a simulation), one shot of actual fellatio, and a brief shot (no pun intended) of an ejaculation. Heard about this film and was intrigued by the premise, plus I like Hitchcockian-style thrillers.