An Unfinished Business, By Boualem Sansal trans Frank Wynne

Rachel and Malrich, the two oddly-named bothers who share narration of this novel, are the sons of a German father and an Algerian mother. Separated by age and inclination, they both grow up in France; one as a successful professional and model immigrant, the other as a semi-drop-out in a hellish estate overrun by extremists.

When news of their parents' death in Algeria reaches them, Rachel goes on a journey that reveals his father's dark past as a Nazi who spent his post-war life erasing the traces: adopting a North African name, and an identity as a benevolent resident of the community in which he settles. Rachel's trajectory takes him on his father's route, to Turkey, Egypt, and the death camps of the Holocaust. The realisation that much of the world he knows was complicit in the horrors of Nazism, and that his own history is intertwined with its evils, causes him to abandon his marriage and then his life. His account of his encounter with this tainted heritage is laced with allusions to the words of Primo Levi.

It is left to his younger brother to complete his unfinished business. Younger and less educated, Malrich has a double mission to complete: the excavation of his parents' history, and his brother's. His is the voice - brash, streetwise and contemporary - that the novel seems to favour, though equal space is given to both brothers.

Malrich begins to draw parallels between his own world (or worlds), and Hitler's Germany. On a trip to his parents' grave, he too is possessed by guilt and leaves with the conviction that Algeria is a concentration camp and all Islamists "Nazi bastards". He wants to kill every last one of them. On his return, the familiar estate is characterised as the Fourth Reich, with a fundamentalist imam and his cohorts in power.

By the finale, it appears that Malrich is ready to take on the fundamentalist cohorts, though if he has a systematic campaign it isn't evident. With his murderous hatred of everything, and his foul-mouthed rhetoric, he seems to share many of the delusions and murderous instincts that he hates.

In a memorable encounter with an imam on the estate, he shocks the older man by attributing and advocating, in a barrage of misfired irony, Nazi methods of extermination to the Islamists. The section is, perhaps, unintentionally humorous, but apart from leaving one wondering how Malrich differs from those he most hates, it also indicates the novel's failure to progress beyond its initial premise.

Rachel's initially tragic reflections soon become a list of facts about Nazi atrocities. His parents, narrated and summarised rather than brought to life, remain interred with all their secrets. The chronology - the protagonists' father is much older than they, and there's a gap of 15 years between the brothers - is a clumsy device to link the Second World War with today.

Belaboured comparisons between Nazi atrocities and fundamentalist excesses begin to burden the narrative as abstract rhetoric. Though he makes an effort to differentiate the brothers' responses, Sansal may have done better to allow the ex-Nazi father his own pages.

The novel's most significant failure is, perhaps, its inability to make Malrich much more than a disaffected mouthpiece for a generation of French Muslims, ill at ease in the place they occupy between racism and religious extremism. Ultimately, at the end of this work of diminishing returns, we are left with little more than a vague, nightmarish vision of Europe in the hands of religious extremists.

Aamer Hussein's latest book is 'Another Gulmohar Tree' (Telegram)