The bisexual novelist and memoirist Violette Leduc was born in 1907, the illegitimate offspring of a maid and her employer. Ledoc's education was interrupted by the first World War, but she eventually returned to boarding school where she had several lesbian affairs, including one with a music teacher who was fired for it. Having failed her baccalaureate exam, Ledoc became a proof-reader for a publishing house and by 1932 had made friends with the author Maurice Sachs, who encouraged her to write. A manuscript for her first novel, L'Asphyxie (In the Prison of Her Skin), was picked up by Simone de Beauvoir, who became her mentor. As with Sachs, Ledoc became obsessed with de Beauvoir. She came to occupy a role: de Beauvoir's tortured "impossible love", a lesbian riposte to Jean-Paul Sartre's ill-defined friendship with Jean Genet.

Ledoc had fans – including Genet and Albert Camus – but no filters, an aspect that is captured beautifully by Emmauelle Devos' storming performance at the heart of this biopic. She bellows. She cries. She blames. She pleads. Sandrine Kiberlain's brittle de Beauvoir remains unmoved, at least on the outside.

Charting Ledoc's life from the second World War until the publication of the bestselling La Bâtarde in 1964, Martin Provost's film breaks down her life into dramatic, emblematic vignettes. Occasionally, there are symptoms of "biography syndrome", wherein character introductions happen with blurbs attached. Conversely, there are episodes that don't contextualise enough for the uninitiated.

One couldn't claim that the story is as persuasive, neat or punchy as the scaffolding for the same director's great 2008 art biopic Séraphine. But perhaps it's only right that the film lacks a narrative through road. As with its subject, Violette refuses to conform to a neat pattern or category. It is, rather, Devos' emotional pyrotechnics and Kiberlain's slow thaw that hold the movie together.