No film featuring Isabelle Huppert can be entirely without interest. But this odd movie from Anne Fontaine is messily structured, self-conscious and preposterous, buried within its own inelegant framing device. The unhappy childhood of a young actor called Marvin is told through childhood flashbacks as the twentysomething adult comes to terms with his sexuality and finally has a staggering stroke of fortune with his career (the sheer flukiness of which is never acknowledged). Finnegan Oldfield plays the adult Marvin in Paris; Jules Porier is his delicate younger self growing up in the sticks, bullied at school and treated with casual cruelty by his unemployed father Dany (a good performance by Grégory Gadebois).

But a number of people turn his life around: kindly headteacher Mme Clément (Catherine Mouchet) encourages him to apply to drama school in Paris; there, gay dramatist Abel (Vincent Macaigne) helps him to achieve emotional stability; wealthy and worldly sugar daddy Roland (Charles Berling) takes an interest, pays for his dental work and – this is the real showstopper – introduces him to none other than Isabelle Huppert, playing herself. The star is evidently entranced by Marvin’s idea for a performance piece based on his upbringing, and agrees to take part, playing his slatternly mother.

The resulting silly-looking show is naturally a massive box-office success, though moody Roland never shows much gratitude to Huppert. I wanted to yell at the screen: a few extravagant thank yous to Isabelle are in order, Marvin. She doesn’t do this for every sullen, whinging drama student, you know. The “reinventing” theme is weak. Of course, college is where you reinvent yourself. But Marvin hasn’t reinvented himself as such: he was always gay, that’s why he was bullied and now he has come out. A disappointment.