Tackling a subject close to home for writer-director Marie Kreutzer, Gentle Monster examines the fallout when Philip Weiss (Laurence Rupp) — a middle-class Austrian documentary maker, father and beloved husband — is accused of watching, distributing and maybe even making child pornography.

Kreutzer’s colleague, the actor Florian Teichtmeister who appeared in her acclaimed feature Corsage, was caught up in a similar case, resulting in his being sentenced to two years in prison. But instead of examining the psychology of accused men, Kreutzer smartly elects to tell the story largely through the eyes of his bewildered French wife Lucy, played by Léa Seydoux in a performance that’s all raw nerves — steely, vulnerable, angry and broken at once.

Kreutzer’s script strives to create a complex view of the many ways people react when they’re involved in situations like this, and how guilt and innocence are never entirely cut and dried. That’s especially clear with a subplot — not entirely necessary, but you can see why Kreutzer thought it was — about the German policewoman (Jella Haase) who is investigating Philip’s case and has her own problems with a difficult, possibly monstrous man at home. Gentle Monster‘s shaded grey morality will frustrate some viewers and draw applause from others; either way, it will provoke lively debates after screenings, which won’t hurt prospects after it debuts in Cannes‘ competition.

The nuclear family at the heart of the story are first met living in the rustic splendor of the German countryside, in a scruffy, characterful house far bigger than this family of three — Philip, Lucy and their six- or seven-year-old son Johnny (Malo Blanchet) — obviously needs. While they have done up Johnny’s room and put together a trampoline in the backyard for him, a test of parental commitment if ever there was one, Philip and Lucy are still sleeping on a mattress on the floor, having not gotten round to buying a proper bed yet. But that doesn’t stop them from having energetic, tellingly choreographed sex while Johnny is at school or asleep, scenes filmed with a woozy sensuality. (DP Judith Kaufmann, who also shot Corsage, lights actors, especially creamy-skinned Seydoux, beautifully.)

There are subtle hints that Philip’s career isn’t going great at the moment. Lucy’s concerts feature her playing piano and singing off-kilter interpretations of pop songs usually performed or written by men like The Cure’s “Boys Don’t Cry” or George Michael’s “Freedom” (arranged by mononymic singer-songwriter Camille, who also provides non-source soundtrack songs), and the shows aren’t exactly making bank. Money, however, doesn’t seem to be the top priority in this trilingual household, where the parents sometimes talk to each other in English and in their native tongues to Johnny.

At one point, Lucy’s very French, somewhat distant mother Eloise (Catherine Deneuve, impactful in her few scenes) observes that Lucy has done the one thing that’s worse for a female artist than having children, and that’s moving to the countryside. When the film pivots toward the big reveal of the story, it becomes painfully clear what she means. Lucy is very isolated in this superficially tranquil domestic setting, separated from friends, far from her mother, dependent on Philip, and not even entirely fluent in German.

That seclusion becomes particularly problematic when one day the police show up at their door with warrants to take away all of Philip’s computers and hard drives. They arrest him for distributing child pornography in a dark web online chat group, where he goes by the handle GentleMonster_87, and suddenly Lucy has to contact his lawyer Lukas (Nils Strunk) and deal with the legal ramifications, as well as all the childcare while shielding Johnny and both her own and Philip’s family from the truth.

But what exactly is the truth? Certainly Lucy doesn’t know, although she’s keen to believe Philip’s initial protestations of innocence, unable to accept that the sweet, droopy guy she’s been in love with for years might also be GentleMonster. Is that version of Philip capable of sharing footage of pre-adolescent children being violated online, as Detective Elsa Kühn (Haase) claims?

By slow degrees, Philip’s story shifts to accommodate the incontrovertible evidence of IP addresses and deciphered cryptography and Lucy struggles to keep up, let alone understand. Like a photograph developing in a bath of chemicals, Kreutzer’s strategies and themes slowly become clearer, and the scene isn’t pretty. Guilt is a metastatic entity here that spreads among nearly everyone connected to Philip and Lucy. Even Det. Kühn is not above blame. Her imperious, elderly father Herrmann (Sylvester Groth) has become disinhibited by dementia and is prone to touching his female caretaker (Patrycja Ziółkowska ) inappropriately, a problem Elsa doesn’t want to face any more than Lucy does.

Ulrike Kofler’s editing deftly draws out the uncomfortable parallels here, and there are other felicitous touches that underscore repetition and change, like twinned scenes where Lucy and Philip both chase after one another in fast-moving cars at different points in the story. Meanwhile, Kaufmann and her team use long, handheld takes holding close usually on Seydoux’s face to create an in-the-moment urgency when needed. The craftsmanship Kreutzer displayed in Corsage is once again much in evidence in this contemporary story that revolves, like Corsage, around a woman trapped in a difficult marriage with few options no matter how much she bleeds herself dry for love, to paraphrase Coldplay’s “Yellow,” sung by Camille over the closing credits.