If Simone de Beauvoir had written Single White Female with nods to Marguerite Duras, the result might be something like this latest Gallic grip-lit sensation. Based on a True Story was published in France in 2015, became a bestseller, won a number of French prizes and was bought for an adaptation to be directed by Roman Polanski. Mais bien sûr.
De Vigan writes “autobiographical fiction”, then deconstructs it, examining where fact meets fabrication, and questioning the very nature of the fictional process. Her last novel, No and Me, was a bestseller in the UK, and Nothing Holds Back the Night, based on her mother’s suicide, brought her both acclaim and notoriety in France.
In Based on a True Story, translated by George Miller, Delphine tells of her inability to write for three years, culminating in defeat by shopping lists and panic at Word documents. The narrative traces this back to the arrival of a stranger, “L.”, at a point when the naturally shy Delphine is overwhelmed by the huge impact of the “personal, intimate book” she has published. L. enters her life precisely when she is “so fragile, so shifting, so liable to crumble”.
L. is a kindred spirit of the same age as Delphine who lives nearby, and rapidly takes on a pivotal role in her life. Glamorous, polished and assertive, L., who is allegedly a ghostwriter, represents much that the narrator aspires to be. But although we know from the outset that this unsettling life-stealer is to become a malign force, and the narrative could so easily follow a loony tunes trajectory towards a Girl on the Train or Fatal Attraction-style implausibility splurge, De Vigan is far too intelligent and feminist to venture into full bunny-boiler territory.
Delphine has two grown-up children and lives partly with her lover François in the country, partly alone in Paris. In her burnt-out hermit state, she is ripe for invasion, but again she is scrupulously honest: “It’s tempting to say that L. broke into my life, with the sole aim of annexation, but that would be untrue. L. entered gently, with boundless delicacy …”
L. makes herself indispensable, but is soon interfering with the direction of Delphine’s work. She dresses like her, answers her emails and writes a preface in her name. Her lies and half-truths mount up, and when L. claims to have attended the same school as Delphine, despite the fact that Delphine has no memory of it, all alarm bells are jangling. The most memorably creepy moment comes when L. actually impersonates the reclusive Delphine, with her full permission, to deliver a talk.
As the novel tracks Delphine’s collusion with this “gradual process of enchantment”, the grip tightens, even as the story-within-a-story ruminates on the nature of fiction. It is all terribly meta: De Vigan plays with the tropes of the psychological thriller, but her work is steeped in philosophical ruminations. L. expounds at length on the subject of autobiographical writing, and her navel-gazing bouts of undergraduate theorising are the only sections that impede the pace.
“Ultimately, I know nothing about L. and never have.” Where is L.? What is she? By the end, we are forced to question narrator reliability, her psychological wellbeing and, once more, the nature of truth. At what level do we read this book? Are symbols superseding mundane old facts? It doesn’t really matter. After such labyrinthine obfuscations, we are left with a deep curiosity that lends the novel an intriguing afterlife. Like it or not, to read this to the full, you are forced to become a hypocrite lecteur.
• Joanna Briscoe’s latest novel, Touched, is published by Arrow. Based on a True Story is published by Bloomsbury. To order a copy for £11.04 (RRP £12.99) go to bookshop.theguardian.com or call 0330 333 6846. Free UK p&p over £10, online orders only. Phone orders min p&p of £1.99.