It's a grey and rainy day in Paris. The trendy Les Éditeurs café where I am due to meet Florian Zeller, the enfant terrible of the Left Bank, is packed with tourists sheltering from the downpour and suspiciously tanned French intellectuals poring over the daily bible of the left, Libération. The head waiter seems delighted to announce that the café is full - until I mutter the magic words "But I'm meeting the writer Florian Zeller here", and a secluded table suddenly becomes available.
Clearly, les intellos still matter on the Left Bank, and Zeller more than most. At 27, he has already written four novels - Neiges artificielles, Les amants du n'importe quoi (translated into English as Lovers or Something Like It), La fascination du pire and his latest, a study of adolescence, Julien Parme - as well as three successful plays. He also lectures on literature at the prestigious Paris university Sciences Po.
As I finish my second café crème, a flustered Zeller appears, as artfully groomed and tousled as any rock icon. Surprisingly, he drops a copy of the centre-right paper Le Figaro on the table beside us. Is he a fan of the right-wing presidential candidate Nicolas Sarkozy? Zeller is guarded in response. He speaks approvingly of attempts by the Socialist candidate Ségolène Royal to bring in "participative democracy", but describes Sarkozy as having "courage".
Despite frequent appearances on TV chat shows, where his opinions are sought on everything from love, women and fashion to writing and world affairs, Zeller is reticent about his political views. In his hit novel La fascination du pire, recently translated as The Fascination of Evil, the narrator dismissively describes politicians as prostitutes. Zeller concurs. "They are a little like prostitutes - they constantly have to sell themselves and seduce the electorate."
He comes to life, however, when describing the challenges that the new French president will face after the elections. "He or she must change the violence and aggression beneath the surface in this country," he says. He isn't referring simply to the violence that broke out in deprived suburbs in 2005, but to a thoroughgoing malaise in French society.
"It is an aggressive depression, rather than a morose or introspective depression, and people lash out at others," he explains. "People are scared even to debate what is wrong. There is so much self-censorship in France, whether it is about national identity and what it means to be French, about the relationship between Islam and Christianity in Europe, or even about the economy."
Zeller's own books probe these tricky subjects. The Fascination of Evil portrays two rather smug French writers who are forced to examine their prejudices and cultural assumptions when confronted by radical Islam on a trip to a book fair in Cairo. The style is lean and spare and immensely readable, paying homage to the author's first literary hero, Milan Kundera. The novel was the result of Zeller's own trip to Cairo: "I was fascinated by Egypt, and had travelled to Jordan as well," he says. "Islam, integration and terrorism after 9/11 and our ban on headscarves in state schools were all much discussed in France. I was in the middle of writing another novel, but this story kept coming back into my head - it demanded to be written first."
His own first-hand brush with Islamism came while teaching at Sciences Po. "They had a bursary for disadvantaged students, so I had several students from the banlieues. I counted many of them as friends," he says. "So I was shocked when I discovered that a lot of these articulate, talented students followed the teachings of Tariq Ramadan, and held some very harsh, radical religious beliefs."
Zeller says that the 9/11 attacks raised profound questions about integration - questions that, again, many in France would rather ignore. "The youngsters who committed those attacks, and the ones who did so later in London, were mostly well integrated, so what made them do it?" He was shocked by a recent British opinion poll which showed that a large number of young Muslims would support the introduction of sharia law. "These are questions we have to discuss, but in France we often censor ourselves instead. I didn't want to push an ideology in The Fascination of Evil," he continues. "It wasn't written to defend or attack an idea, but to explore it, and create around it a believable narrative, which is sometimes a sad or painful one."
Liberally spiced with musings on life, death and the meaning of love (and plentiful sex), Zeller's tale of the "clash of civilisations" has reinforced his precocious literary success. The novelist Françoise Sagan asked him to write a play while he was still a student at Sciences Po. He has since become friends with both Kundera and the adulte terrible of French literature, Michel Houellebecq, whom he describes as "surprisingly sensitive and gentle" - a description at odds with Houellebecq's public image as a difficult and sometimes foul-mouthed misogynist.
But Zeller is full of surprises. Far from being the privileged literary brat one might expect, he grew up in Brittany and later in the Paris suburbs, the middle child of three. Zeller's mother was a fortune-teller and mystic, separated from his father, who was often absent working in Germany. His family was neither literary nor theatre-going, though he says his mother could hardly complain about his choice of an insecure, "unserious" writing career while she read her tarot cards.
France, Zeller adds, must change its attitude towards those who succeed. "People here don't like success." It is said with feeling - Zeller has been the target of much literary bitchiness. "There's a kind of extreme verbal violence between authors and journalists and critics in France," he sighs. And when I mention his name to literary friends on the Left Bank, they laugh. "He's a brand, not a real writer," says one. "Overhyped and overblown. But he looks good on TV," scoffs another. "Lightweight. His writing is to literature what elevator muzak is to orchestral symphonies," comments a contemporary from Sciences Po.
"I hate that sense of rage in France," Zeller says sadly, with a final shake of his blond mop, as he ventures out to the Salon du Livre, the annual book fair where French writers gather to compare advances, check who's still alive and, most of all, complain about each other.
Caroline Wyatt is the BBC's correspondent in Paris