Sumptuously realized and devilishly adroit in its provocations, “The Last Mistress” finds Catherine Breillat, the French director notorious for what the characters in her films do while naked, taking on a 19th-century costume drama. Not to disappoint, though: The scintillating corsets do slip off, most often to expose Asia Argento, “the old mistress” of the movie’s French title and Jules-Amédée Barbey d’Aurevilly’s 1851 novel, which was as scandalous for its time as Ms. Breillat’s candid excursions through the labyrinth of human sexuality have sometimes been for ours.

Ms. Argento, who has recently been chased by demons in her father’s “Mother of Tears” and menaced by Hong Kong hoodlums in “Boarding Gate,” is as much huntress as hunted in this go-round. She plays La Vellini, a Spanish courtesan described by one admirer as “a capricious flamenca who could outstare the sun,” and who may also prove to outlast demands on her lover, Ryno de Marigny (Fu’ad Aït Aattou), and his impending marriage to Hermangarde (Roxane Mesquida), a blue-blooded virgin wholly smitten with her rakish, pretty-boy fiancé.

The story largely unfolds in flashbacks, as Marigny confesses his philandering ways to the Marquise de Flers (Claude Sarraute), Hermangarde’s interrogative grandmother, who culls from the dandy the tortured details of a decade-long romance with La Vellini that is more hate than love. The talkiness, the drawing-room intrigue, the frilly garments, and the slippery assignations might suggest all too much a “Dangerous Liaisons” redux. But Ms. Breillat is much too clever for that. What makes “Mistress” so deliciously fun is the way she uses the narrative as a template for her own playful (and fever-ridden) ideas about the anarchy of passion and the disorder of decorum.

The sets and settings give the director a chance to splay the naked and semi-clothed bodies she loves so well in tableaux that more immediately suggest “The Nude Maja” than Taboo magazine, while subversively tricking out her lovers’ personae with all manner of outré behaviors and affectations.

Perhaps the most outrageous is that the human firebomb Ms. Argento is intended to be a physically unattractive woman, even “a little Moorish,” who manages to suck a younger man into her carnal whirlpool despite the fact that he has a dewy-eyed nymphet waiting up late for him. The whirlpool part makes perfect sense, especially when La Vellini shows up at her opera box brandishing a spit curl that forms two halves of an apple-shaped derriere. But the rest belongs to the rewrite, which allows the actress her indomitable sway. At once haughty and masochistic, La Vellini variously cross-dresses, suckles vampire-like at her lover’s gaping chest wound after her elderly husband shoots him in a duel, and indulges in howling Algerian desert sex when, years later, the daughter she has with Marigny dies from a scorpion bite and is consumed in a makeshift pyre.

These people have baggage.

All the same, the film’s elegant tone is remarkably sustained. It’s as if merely placing Ms. Argento into a scene is enough of a transgression in itself — the story pausing for a moment as La Vellini makes out with her handmaiden, or licks greedily at a tiny cup of vanilla ice cream (ice cream?) in her carriage while gazing with contempt at her future lover. That gaze fixes the audience as well, almost knowingly. Camped out on the beach near the seaside home Marigny has claimed, La Vellini straddles her perch and chews on a stogie. When the pregnant Hermangarde finds her there, dormant like the eye of a hurricane, the old mistress nails her with a cockeyed glance and a crooked smile. She’s a force of nature, and she won’t be reckoned with.

The same could be said of Ms. Breillat, whose atypical reserve does nothing to diminish her twitchy, psychosexual themes, but rather lends them a satisfying and incisive focus.