In every way a dreary, unattractive lump, the 12-year-old title character of French provocateur Catherine Breillat's Fat Girl receives no affection and thus has the benefit of seeing the world for what it really is—or at least what Breillat thinks it is—with a cold, dispassionate eye. Early on, she declares to her older, conventionally attractive sister that she wants "to be broken in" by someone who doesn't love her, as if love would be certain to taint her rite of passage. Sentiments like these are common to Breillat's work: From her 1976 debut A Very Young Girl to the minor arthouse breakthrough 36 Fillette to the scandalous (and deceptively titled) Romance, love and sex have been incompatible bedfellows. To her way of thinking, love can confuse the issue in emotionally treacherous ways, exposing people when they're at their most vulnerable. For roughly 90 of its 93 minutes, Fat Girl demonstrates this cynical philosophy with subtlety and unnerving tension, as Breillat pushes a familiar coming-of-age scenario into unusually chancy terrain. Then, in those last three minutes, she pushes too far, ending in a flurry of cheap provocation that tarnishes everything that preceded it, smothering shades of gray in a thick coat of black. Anaïs Reboux and Roxane Mesquida star as bitter sibling rivals who share a room in a gated vacation house with their bourgeois parents. After they meet a handsome Italian lothario (Libero De Rienzo) in a café, Reboux plays silent witness as her virginal older sister falls under his spell and later invites him to sneak into their room after hours. In Fat Girl's bravura centerpiece, a long and relentless sexual negotiation, De Rienzo seduces Mesquida with a salesman's snaky charm, softening her up with sweet talk and insincere promises, letting her feel a slight sting of resentment, and then using "love" as the ultimate bargaining chip in getting what he wants. As a standalone scene, it's a remarkably intricate and credible feat of emotional exploitation, but when measured against the finale, it suddenly looks simple and crude in retrospect. Breillat manages to slip in one more terrific sequence before it's over, in the form of a menacing highway drive worthy of Psycho and Duel. But once her sexual politics snap cruelly into focus, Fat Girl becomes not just unsettling, but repellent.