Lily is a fine upstanding Deutschemadchen, making babies for Hitler's troops - rather more of Hitler's troops than her husband suspects, as she shags her way through Berlin while her husband is at the front. Felice is a Jewish Communist lesbian working undercover for the Zeitung, stealing lists of names of Jews to be deported from her boss who is a big Nazi cheese, and helping smuggle people out of Germany. She is part of a small underground network of Jews who stayed in Berlin at great personal risk to work as spies and resistance. Her circle of young women friends provide each other with jobs, food and love. When Felice's girlfriend introduces her to her employer, Lily, a passion is set in motion that endangers the whole organisation. At first, Lily is charmed by Jaguar's erotic poems and she slowly becomes deeply involved with Felice, struggling against her strict upbringing and the impossible situation. When Felice finally tells her that she is Jewish, the whole cinema holds its breath.

This film has been described as a lesbian Romeo and Juliet, and in a sense it's true. Both Felice and Lily are immature as lovers when the film opens, both high desirous and desirable, given to flings and flinging away partners when they are done. Their affair is a learning process for them both - a learning of both the limits and limitlessness of desire. Even in her precarious situation, Felice pursues Lily ardently, and the film makes a study of the small and great betrayals human beings make in war. Lily's husband is painted as more of a boor on screen than he comes across in the book, but the film retains the nuances of Berlin life so rarely seen in movies about the war era. Lily is not the only one to come to accept and protect Felice as a Jew, and the girls makes themselves a life that mingles daily survival and wild parties that - while dangerous - suggests alternate histories within our over-riding understanding of Hitler's Germany. The persistence of the human spirit in love is rendered here in desperate vivid colours.

So far, so worthy. A film tailor-made for niche-market film festivals. Yet there is more to Aimee and Jaguar than that. Its handling of the documentary material is always close, but given cinematic character not only by the rich palette of the designer and cinematographer - clothes act as symbols for moods - but by the strong script which isn't afraid to put opinions, and even poetry, in the mouths of its characters. The ensemble playing on both sides - Felice's friends, Lily's family - is material to the persuasive vivaciousness of the film. One feels that the director has given his movie the same character as Lily and Felice's relationship: beautiful amid but not in ignorance of the horror, joyful because aware that time is short, and tragic without being morbid. The inventiveness of the intimate scenes between the lovers, which initially use clothing and food as code for love, and develop into dancing, kissing and sex, separates the film from its documentary nature. Cinematographically and structurally, it has the feeling of classic war films like Brief Encounter, where the relationship becomes a metaphor for the politics of the outside world.

The sensuousness of the movie is a victory over a film industry that would feed us our historical cautionary tales in big budget digitised extravaganzas. As in Pearl Harbor, the love of a good woman represents both salvation and the drive to fight evil, but here the woman herself enters the fight on even terms. And those even terms are rare enough. Perhaps describing the film as a lesbian The English Patient might come closer to both the intensity of the passion and the opposition between the affair and the world raging outside. But the tragedy here is not personal in its execution. In the end, the state intervenes, marking in that single act the destruction of privacy and private space that Fascism necessitated.

Aimee and Jaguar is a painstaking effort to reconstruct that private space, to bring a secret history to the screen without making of it a freak show or an object lesson. The carefully-wrought individual characters argue that this is their story, a single voice speaking for itself, restoring the individuality that the Nazis took away by transforming the world to mass movements and numbers. That Felice and Lily, a Jewish lesbian and a Catholic Nazi mother, should speak with a single voice in this film is a triumph over the world Fascism would have made.

Sophie Levy