Oscar season rings in the annual cycle of gossip, debate and speculation about disputed nominations and conspicuous snubs, and this year one major story concerns the case of France fumbling the bag. Anatomy of a Fall, a courtroom thriller about a writer suspected of murdering her husband, took Cannes by storm last summer to win the Palme d’Or – making director Justine Triet the third woman to win the festival’s top prize in its 76-year history – before becoming a box office hit in France. It was, in the words of the Hollywood Reporter, “one of the rare movies which checked all the boxes for a strong Oscar entry: not only was it a critical darling that resonates with wide audiences, it’s distributed by [prestigious US film company] Neon, which shepherded Parasite to a best picture win.”

Though when the time came for France’s Oscar committee to select the film that would represent the country in the best international feature category, they opted instead for The Taste of Things, a slow-burning period romance that doubles as a love letter to food. Trying to objectively compare works of art can be a fool’s game: The Taste of Things film-maker Tran Anh Hung was named best director at Cannes, and critics have praised its expertly choreographed sequences and heartfelt storytelling. But the choice came as a surprise in the industry, seen as an instance of France’s old guard shutting out the new. There were rumours that Triet angered ministers with her acceptance speech at Cannes, in which she criticised Emmanuel Macron’s “neoliberal government” and its “commercialisation of culture”. In any case, The Taste of Things did not get an Oscar nomination, Anatomy of a Fall received five, leading to questions in France about why they lost their best chance to win their first Oscar for best international feature since 1992’s Indochine.

What was behind Anatomy of a Fall’s surprise success? The murder mystery has taken off in recent years – perhaps there is something comforting, in a time of permacrisis, about a genre that narrows the world, and presents questions that aren’t existential or rhetorical but the simple: whodunnit? – and Triet’s film intelligently plays with genre conventions. It gives us some clues – a trail of blood, splattered across a shed – while leaving other details tantalisingly out of view (the family dog, Triet has said, is probably the only witness to have seen what happened. Bring him to the stand!) The moment we think the case is closed, fresh ambiguities keep us guessing. Tying it together is a masterful performance by Sandra Hüller, whose protagonist – also named Sandra – seems as slippery as she feels real: she comes across as vulnerable, closed off, intelligent and inscrutable at once. “Did she do it?” a friend asked me. My guess was that she seemed like either a normal albeit remarkably strong innocent person, or a guilty mastermind. Though, as the latest season of The Traitors shows, it’s extremely easy to be taken in.

Underneath the courtroom theatrics is a simple question: can you ever really know another person? While Triet partly drew from courtroom dramas, another inspiration was Noah Baumbach’s film Marriage Story (Triet wrote the script for Anatomy of a Fall with her husband during lockdown, though they deny parallels between them and their characters). Tucked into the larger legal procedural is a more intimate, but no less important, story of the slow disintegration of a marriage, a subtle yet piercing examination of the small resentments that topple once loving relationships. There’s the jealousies over her flourishing literary career against his frustrated attempts to write; his resentment over perceived imbalances in childcare efforts; her affairs. During the trial, her late husband’s psychiatrist presents a portrait of a man pulsing with anger about her slights. She protests, saying that that was not all that he was. You only see certain sides to people, she suggests, echoing the film’s broader interest in the unknown and the unseen.

Ironically, Anatomy of a Fall would have been the frontrunner in the international feature category, and now faces a more crowded field in best picture. But praise is due for a film that takes the familiar – unhappy marriages, courtroom procedurals, the ethically compromised thrill of true crime – and produces something that feels new and lingers long in the mind. When the story ends, and one version of events is offered up and fragilely agreed upon, the mood is not one of triumphant closure but an uneasy second guessing. Perhaps that mystery, and the idea of forcing the audience to come to the limits of their understanding, is the point.