Voyeuristic story-in-a-story intrigues to end

The teacher is a veteran of the French school system, not burnt out but resigned to the mediocrity of each new crop of high school sophomores. That first assignment – “Write about what you did last weekend” – confirms what he tells his gallery manager wife: “This is the worst class I’ve had in my life.”

But one 16-year-old boy, Claude, takes it seriously. He describes a classmate he selected, a somewhat dim kid whose life he’d love to have, whose house he longed to gain entry to. And he did, taking in details – the sports-crazed dad beaten down by a job that includes petty humiliations from his boss and Chinese clients, and “the singular scent of a middle-class woman,” his classmate’s fetching blond mother.

He’s ingratiating himself into their lives. He’s observing, passing judgment, telling their secrets. And he knows how to make the essay a cliffhanger.

“To be continued.”

French director Francois (“Potiche”) Ozon’s latest is an adaptation of a play, a satire of talent presented to those who don’t have it but recognize it, a spoof of mores and the writer’s craft, and a “bildungsroman” (coming-of-age tale) with hints of a creepy stalker-thriller about it.

Veteran character actor Fabrice Luchini (“Moliere,” “The Girl from Monaco”) is Mr. Germain, the cynic stuck teaching the unwilling at Gustave Flaubert High School. Ernst Umhauer is Claude, the precocious boy whose literary bent intrigues his teacher but alarms the teacher’s wife (Kristin Scott Thomas).

“He needs a shrink,” she warns (in French, with English subtitles). “He could be dangerous.”

But night after night Jeanne sits, utterly absorbed by her husband’s narrations of Claude’s tale of Rapha (Bastien Ughetto), his father (Denis Menochet) and his most fetching mother (Emmanuelle Seigner of “The Diving Bell and the Butterfly”). The boy violates their trust and spies on them. And that which he doesn’t observe directly, he imagines fancifully. Willing or not, the Germaines become voyeurs, just like Claude.

Germaine begins with “the boy deserves encouragement” and soon imagines himself in the scenes with Claude, adjusting the focus of the narrative, steering the boy away from melodramatic flourishes and “improving” (he thinks) this tale.

The acting dazzles; Thomas has a couple of amazingly unfiltered, flattered and flabbergasted reactions.

Ozon has some fun with this material, playing around with versions of reality, inserting characters in scenes that Claude rewrites and adjusts, serving up the odd comic twist. Ozon seems as willfully uncertain of its direction as Germaine. “Is it parody?” Perhaps a goof on the author of “Madame Bovary,” Flaubert, whose name graces the school?

“Flaubert doesn’t JUDGE his characters,” Germaine lectures. But he’s plainly titillated by the kid’s writing exercise. His job is threatened and his marriage turns testy as he grows more obsessed by how this chilling, sadistic tale will come out.

But for all its pleasures, as Germaine nudges Claude toward that “ideal” ending that will make the reader say “I never saw that coming” and “It could not have ended any other way” at the same time, one only wishes this absorbing but melodramatic film had taken that advice.