I admit I was stumped by this film. It started off plausibly enough, with some great opening credits, and introduced us to one of the two leads, Ozon’s favoured actor Fabrice Luchini, here playing Germain, a disillusioned and beleaguered high school teacher – quite a contrast to his last Ozon role as a tiresome, philandering husband in Potiche.

He sets the class an assignment, ‘what I did last week’, and is bemoaning the low standards of both literature and teenage (lack of) activity to his wife, Jeanne, the ever-gamine Kristin Scott Thomas, when he comes across a proper essay. Intrigued by this latent talent, he soon makes it his mission to encourage the budding author.

Claude, played by young newcomer Ernst Umhauer, takes as his subject matter the life of his friend Rapha, in whose ‘perfect family’, he insinuates himself. Having lost his mother, he is particularly intrigued by the ‘scent of a middle class woman’ of Rapha’s voluptuous mother (Emmanuelle Seigner) and the alpha-male presence of Rapha Sr (Denis Ménochet). Germain’s eyebrows rise, but he begins a headlong descent into setting Claude an intellectual exercise on the role of the novelist – to record what is real and to avoid caricature, gossip, farce and ‘Barbara Cartland’ (pronounced the French way!). He gives him Dickens, Hugo and Flaubert to read as role models.

In trying to please his teacher, Claude is conflicted and we are puzzled – what is real and what is imagined? Germain criticizes Claude’s factual telling and encourages him to alter the story, for the sake of art. Claude re-writes scenes to please his muse but in so doing enters dangerous territory. And here is where I get troubled. Ozon introduces Germain as voyeur into some of the scenes, and the little voice in my head says, no sensible person, no teacher, would act like this. What is really going on here? This is not a straight narrative, not even a psychological thriller. This is mind-games.

As a result I broke my rules and did some research into what it might all mean. Bingo! How could anyone but a serious French film buff know that this is the concluding part of a trilogy of films exploring the role of the writer? The first film was Swimming Pool, starring Charlotte Rampling; the second Angel, with Romola Garai, and this is the conclusion, said to be the most autobiographical. Ozon is homosexual and many of his films deal with gay themes: here we have Rapha’s adolescent attraction for Claude; Germain’s ambiguous attraction to Claude, so ambiguous that it worries Jeanne enormously; and Claude’s ability to flirt with all his admirers to achieve his dream.

It is, as only French films can be, an intellectual essay on both the meaning of the role of the writer in art, and whether photography tells the truth or is only the jumping off point for illusion – and there are allusions to Daguerre and the development of the art in the early 1830s. Ozon references Baudelaire who, writing on Balzac, he calls an ‘observer’ not a ‘visionary’. Hence the complexities that face Claude’s attempts to deliver his weekly essay: should he tell the truth or should he embroider to reflect his desires? He always ends, ‘à suivre’, punchy in French, more prosaic as ‘to be continued’ .