How do you judge an author? On the novel that blew 20th-century literature apart, which stunned Jean-Paul Sartre, Henry Miller, William Burroughs, Jack Kerouac and Allen Ginsberg, to name just a few?

Or do you judge him on sick outpourings of anti-Semitism that clamoured for the persecution of Jews?

France is in the grip of this dilemma as it prepares for the 50th anniversary of the death of Louis-Ferdinand Celine.

Arguably the greatest shock writer of the 20th century, Celine - the pen name for Louis-Ferdinand Destouches - leapt to fame in 1932 with Voyage au Bout de la Nuit (Journey to the End of the Night), a semi-autobiographical work.

Voyage portrays a young man pitched into the industrialised butchery of World War I, dehumanised by work on the Ford production line and, as a doctor, adrift in a sea of misery in the poor Paris suburbs of the Depression.

Any reader expecting to encounter an Albert Schweitzer will be disappointed from the novel's first words.

Voyage is a tableau of fear of death, of disgust and boredom. It seethes with hatred - of the class system, the bullying power of money and the moral posturing that had driven Europe to destruction.

It spits bile and repugnance at human physicality, at the messiness and failed dreams of life.

The work had the literary impact of a tsunami.

Voyage, followed in 1936 by Mort a Credit (Death on the Instalment Plan), swept all before it.

French-language writers inspired by Celine's bleakness included Jean Genet and Samuel Beckett. Celine's dark twisting of perception inspired Sartre's novel Nausea, the ground-breaking work of existentialism, and La Jalousie, Alain Robbe-Grillet's portrayal of an obsessive husband.

The impact on English-language authors was arguably even greater, touching directly or indirectly on style-driven writers from Tom Wolfe to "gonzo" journalist Hunter S. Thompson.

"Celine is my Proust!" exclaimed Philip Roth. "Every writer is in his debt," said Kurt Vonnegut.

For Voyage alone, Celine would have secured an eternal place in the literary pantheon. But his fear and paranoia, no doubt caused or worsened by wounds and trauma sustained in the trenches, plunged him into virulent anti-Semitism.

In a series of pamphlets written up to and during World War II, he poured out a hatred of Jews, all penned in the same emetic, tireless and intense style as Voyage.

"I find Italian anti-Semitism lukewarm for my taste, bloodless, inadequate," he wrote of race laws approved in Italy in 1938. "I find it dangerous. A distinction between good Jews and bad Jews? It makes no sense."

Branded a collaborator after the Liberation, Celine took refuge in Denmark until he was amnestied in 1951. On his return to France, he spent a year in prison.

Controversy over this Manichean character has never gone away, just as interest in his work has never dimmed: sales of Voyage still average 40,000 copies a year.

Debate has reached boiling point as the 50th anniversary of his death, on July 1, 1961 at the age of 67, draws near.

At the start of this year, the French Government included the anniversary on its official list of "national celebrations". That stirred protests from some intellectuals and Jewish figures.

As their campaign grew, Culture Minister Frederic Mitterrand gave ground and scratched Celine's name from the celebrations list, a move derided as irrelevant by Celine biographer Francois Gibault, who is also lawyer to his 98-year-old widow Lucette Destouches.

"It's not up to the ministry to determine who is good, bad, talented or a genius," Gibault said. "Celine is celebrated by his readers and by students or teachers around the world who study his work. That's the only celebration worthy of the name."

The debate has sparked the question whether his banned anti-Semitic pamphlets should be published in academic form, and what one should look for in a hallowed artist - and why.

"As a writer, he should be on the list," said Henri Godard, a professor at the Sorbonne and whose new biography of Celine has been widely acclaimed. "On other hand, he obviously does not deserve a place as an exemplary man with high moral virtues."

An extract

The worst part is wondering how you'll find the strength tomorrow to go on doing what you did today and have been doing for much too long, where you'll find the strength for all that stupid running around, those projects that come to nothing, those attempts to escape from crushing necessity, which always founder and serve only to convince you one more time that destiny is implacable, that every night will find you down and out, crushed by the dread of more and more sordid and insecure tomorrows. And maybe it's treacherous old age coming on, threatening the worst. Not much music left inside us for life to dance to. Our youth has gone to the ends of the earth to die in the silence of the truth. And where, I ask you, can a man escape to, when he hasn't enough madness left inside him? The truth is an endless death agony. The truth is death. You have to choose: death or lies. I've never been able to kill myself.

From Journey to the End of the Night