Personal Shopper” is the scariest movie about buying Chanel dresses you will ever see. Popping up on virtually every “Best of 2017” list, this stylish, moody Kristen Stewart film is as hard to pin down as the ghosts that occasionally inhabit it.

Stewart stars as Maureen, a disaffected, slouchy lass who seems rather miserable performing her extremely glamorous job selecting and delivering very fancy clothing and accessories for a famous actress. She remains in Paris despite her desire to leave, because of a pact she made with her recently deceased twin brother.

Both Maureen and her late brother, Lewis, share a heart defect, which killed Lewis, and they also share psychic abilities as mediums who are sensitive to the presence of ghosts. In addition to shopping at Cartier for her boss, Maureen spends her time at the empty country house where her brother died, looking and waiting for the sign he promised he would send from beyond.

Helmed by the moody Stewart, “Personal Shopper” is at times too inscrutable for its own good, and by that I mean slightly boring, in a way that seems intentional and is therefore a bit irritating. But this makes the frightening parts genuinely startling and scary. Based in a believable reality, this ghost story becomes plausible, and our emotional investment in Maureen’s search for her brother’s spirit is genuine.

In the midst of these uncanny goings-on, there is also the vicarious pleasure of watching Maureen paw through all that couture. Vicarious pleasure is actually a big part of her character, and her problems. The film is called “Personal Shopper” and not “Ghost Sensing Medium” because her weirdly unsatisfying job starts to torment her. She complains she has no time to do anything she really cares about, such as drawing, but she is also increasingly obsessed with wearing the clothes she chooses and delivers — something she has been explicitly forbidden from doing.

The Gothic trope of doubling is put to use in this modernized horror story, as the actress-slim Maureen stands in on photo shoots for her absent client, and her relationship with the largely unseen movie star she works for is explored in a long conversation with the star’s mysterious, menacing lover.

After this conversation, Maureen begins receiving texts she believes are from her late brother. A violent crime only deepens the mystery of their source, and plunges Maureen deeper into despair, confusion and real danger. Stewart begins to do a bit of acting at this point, too.

Even when “Personal Shopper” is just a moody character study of an interesting-looking woman skulking around the Chanel showroom, it’s unusually compelling. Stylish French director Olivier Assayas (“Clouds of Sils Maria”) again explores themes of fame, personal fulfillment and mortality with his androgynous muse, Kristen Stewart. It’s hard to believe the end of this film is from the same story as the beginning, but the disorienting mood leads to a truly memorable finale.

The pacing, which has its violent apex before the end of the film and then lingers on a quiet but extremely compelling final act, ultimately supports the theme of life and the afterlife. The story is about Maureen continuing to live after a death and grappling with how to do that when she is truly haunted.

“Personal Shopper” is currently available to rent.