These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
Complete Monster: There are quite a few horrible people in the film, but none compare to La Tenia, the pimp and rapist, who is simply a monster of a human being with no redeeming values. He severaly beats up his hooker because she did something wrong, and then decides to rape Alex when he spots her alone overseeing this. He rapes her excessively long just to draw it out more, and finally ends it by repeatedly bashing her head against the pavement, sending her into a coma and miscarrying her baby. Note that he actually subdued her during the rape without inflicting physical injury (the threat of a knife and then his own greater strength and weight were sufficient,) and all of Alex's injuries came after he had finished, proving that he beat her purely for the sake of hurting her even more. He's not even sexually attracted to the gorgeous Monica Bellucci in Vapor Wear (he actually says while raping her that he doesn't "normally like this". He just rapes her because he can. It's also heavily implied that this is hardly the first time for him either. The next (previous?) time we see him, he's in a club with a bunch of other sexual deviants, and is overjoyed to watch the wrong man get beaten to death by Alex's friends right next to him, both because he gets away and because he loves witnessing graphic murder.
Marcus' initial fight with the suspected rapist, and then Pierre's extinguisher bludgeoning of his face.
La Tenia when he rapes and beats Alex.
Nausea Fuel: This film makes few allowances for those that suffer from motion sickness. The vertiginous camerawork and garish red lighting combined with the intense droning soundtrack caused a few people to vomit at the premiere. Low-frequency sound was also used in order to disorientate the audience.
Unfortunate Implications: The film was accused of being filled with homophobia, as the gay characters featured in the Rectum Club are perverts who hit on Marcus, and one of them tries to rape him. While the almost-rapist is beaten to death, another gay man watches and masturbates. Played by Gaspar Noé himself.