Actress Virginie Efira may be Belgian, but she has an air of game openness that seems American. One minute she’ll look like a sun-kissed Kim Basinger, but middle-age worry wears heavily on her face in the next. This dual quality serves Efira brilliantly in Justine Triet’s smart, sexy, and over-the-top Sybil, in which she plays a meddling psychiatrist who can’t always see the warning signs when glamorous drama is about to give way to the unwanted, more embarrassing kind.

Sybil, a settled-down maman and therapist, rashly throws over her longtime patients to concentrate once again on long-abandoned literary ambitions. One emergency client comes over the transom, though: Margot (Adèle Exarchopoulos), an up-and-coming actress in deep romantic crisis. Margot’s youth, magnetism, and raw emotions reawaken memories within Sybil of her own brushes with boozy abandon and eyeball-melting sex. Sibyl quickly becomes consumed with Margot’s life. Before you know it, she’s on a plane to an Italian island film set, sticking her nose (and other parts) into a bizarre love triangle between Margot, her leading man (Gaspard Ulliel), and the film’s unhinged director (Sandra Hüller from Toni Erdmann). 

Sybil includes many narrative strands to draw us in. We catch glimpses of Sybil as mom, doctor, avid sex partner, and even karaoke singer—a viewfinder cascade that reflects the many roles accomplished women play in contemporary life. But the showbiz satire that hurtles forward two-thirds of the way through is the sharpest of the lot.

Artistic temperaments flare on the set. Background intrigue rustles like the noise of scurrying rats, and Hüller’s character tosses off withering asides before exploding in a jealous rage. (Hüller comes close to stealing the movie from two magnetic co-stars.) Ulliel exudes evil charisma as a preening, predatory leading man, and Efira’s Sybil loses control as she falls under the spell of the charged atmosphere, indulging in an impulsive decision that will end in shame and tears.

Erotic scenes and clever parody can make Sybil seem like a lark, if a melodramatic one. But the film is anchored by shrewd, relatable observations about human foibles: an instant when a character lies to herself, a night of molten intimacy where both partners sense the beginning of the end, and the moment when a child discovers that the surrounding adults are not quite sane. Editing picks up and leaves off at points that keep you guessing. Rue leavens the film’s grand gestures.

Triet has put Sybil together in distinctive style. She offsets the exploits of unhinged characters with formal control, ridicules them but sees the good in them anyway, and gives talented actresses plenty to do. It’s a fast-paced, absorbing watch, and mostly a pleasure all the way through.