Nothing does more to recommend a film than the knowledge that it received boos at Cannes. The bovine mass made itself heard at the end of Olivier Assayas's strange, rambling (I guess) meditation on loss, but even if they had thrown offal at the screen the film would still have proved hard to embrace. On the surface, Personal Shopper looks like a ghost story made by somebody with nothing but disdain for the medium. An admirably game Kristen Stewart – in virtually every shot – plays Maureen, personal shopper to a vain fashion maven who can't speak without shouting. In that sense you could see the picture as a (hem, hem!) spiritual sequel to Assayas's Clouds of Sils Maria, in which Stewart was factotum to a great actor. But Shopper is odder even than that film.

Maureen has recently lost her brother to a heart condition that she shares. “He was a medium,” she explains in a face straight even for this deadpan actor. She is waiting for a sign from beyond the grave and, when it comes, it proves more explicit and less helpful than expected: a vomiting grey special effect that is part Rentaghost and part low-end J-Horror. There’s more. A seemingly malign entity that knows too much about her movements begins texting her in threatening manner. While this is going on, she travels from Paris to London in search of nauseatingly expensive trousers for her employer.

That synopsis makes the picture seem more interesting than it actually is. Attempting to refit the tropes of supernatural cinema to middle-brow ends, Assayas ultimately delivers a ghost story with no scares wrapped around a psychological drama with no intellectual purchase. As he demonstrated 20 years ago with Irma Vepp, this interesting director can do better with similar amalgams.

No blame should attach to Stewart, who works hard at making sense of it all. For much of the film, however, she has the air of an actor desperate for direction. And nobody could say the former Bella Swan doesn’t have past experience of the supernatural. A puzzler.