Past old men playing boules in the square, and pollarded trees which look like upturned claws, past crush barriers fluttering with the lists of vanished victims, Arno Klarsfeld has arrived by in-line skates at the Palais de Justice in Bordeaux. It is the flippant entrance of someone who seems too young to be a dedicated Nazi hunter, but that is part of Klarsfeld's puzzle. For the past six months he has been one of the chief civil prosecutors in the trial of Maurice Papon, his own wayward arrogance matched by the octogenarian's unflinching contempt for anyone who dares to accuse him of crimes against humanity. But Papon's scorn hardly troubles Klarsfeld, whose paradoxical nature makes him a constant irritant to his dustier colleagues, and an icon on the street. He is that singularly Gallic creature, the pin-up antihero both glib and deeply serious; the moody, indulged, and impetuous bad boy

redeemed by good intentions.

Yet the question which cannot be avoided now is whether Klarsfeld has actually helped or hindered the case against France's former high-ranking administrator in the last war's pro-Nazi Vichy regime. Papon, who is 88, signed the deportation orders for 1690 Jews from the Bordeaux region, most of whom perished in the Germans' death camps. Last Friday the jury was expected to deliver its verdict, but because of the defendant's physical frailty that word postponement has dogged this trial from the beginning and on Wednesday it prevailed again: in the early hours of that morning Papon's wife, Paulette, died from a long battle with cancer, and the man who, only weeks previously, had claimed in the dock that he had cried with her for the Jews on Christmas Day in 1943, was taken immediately by police escort from his secret and guarded Bordeaux address to the family home in Gretz-Armainvilliers, a

suburb of Paris.

Will the immediacy of this bereavement sway the outcome? Paulette Papon was buried late on Friday, and the trial is expected to resume this afternoon, which means its result could be known on Wednesday. But, shrugging with frustration, Klarsfeld says that, whatever the sentence, ''Papon will never go to jail''. Still, it was only in January that he himself practically jeopardised the entire proceedings by requesting the removal of the presiding judge, Jean-Louis Castagnede, a bizarre demand, since withdrawn. Klarsfeld claimed that the judge had concealed from the court his own Jewish connections - according to the bold prosecutor's investigations, one of Castagnede's uncles married a Jewish woman whose two sisters, mother, and father were plucked from Bordeaux and sent to their deaths in Auschwitz.

Privately, the judge let it be known that he was astonished by the revelation because that side of the family was unfamiliar to him. But, in a further twist, magistrates called for criminal charges to be pressed against Klarsfeld, claiming his accusation had ''gravely slandered'' Castagnede. Of course, the real antipathy between the two had begun months before when the judge ruled that Papon, because of his age and health - he underwent a triple by-pass last year - should remain on bail for the trial's duration. For a few days Klarsfeld noisily employed a token boycott of the proceedings, and he still maintains that the concession is evidence that Castagnede wants an acquittal. Papon's bail, he argued initially, made the defendant the master of the trial, ''leaving him free to sabotage it whenever he wants, even on the eve of the verdict''. Set against this latest adjournment, that declaration

now tolls with an irony so unfortunate and stinging it sounds not like prescience but malice. Today Klarsfeld remains unrepentant. ''Notoriety,'' he declares, ''is a weapon.'' But perhaps the very brashness of that sentiment only sharpens his enemies' own ammunition. So is he a liability or does the eccentric behaviour mask tactical cunning? As France seeks to purge its repressed shame about the collaborationist past, Klarsfeld's supporters explain his insolent modernity as the means by which he makes war's atrocities relevant to the conscience of a new generation.

''All through the trial I have been criticised by both sides,'' he says. ''But it hasn't hurt me because when you have a cause you fight for it all the way. You don't care about what others say and, anyway, when both sides attack, well you can think that what you do must be OK. Of course, it also happens that you can be wrong, but this time, yes, I think I'm pretty right.''

Klarsfeld is 31, dark and sulkily handsome, with the flagrant hauteur of a hard rock philosopher from the Sourbonne rather than the bib-and-tuckered formality of the French Bar Association. His fluent English carries an overlay of New Yorkese from the time he spent in the early nineties, working with influential corporate lawyers in Manhattan. But even then the cause he refers to now was imprinted on him like a birthmark: he is the eldest son of Serge and Beate Klarsfeld, whose unremitting quest for justice on behalf of Holocaust victims has made them sombre celebrities in France. It led, most famously, to tracking down Klaus Barbie, the ''Butcher of Lyons'', in his Bolivian hideout, and at the subsequent trial in 1987 Klarsfeld senior led the prosecution. Barbie, jailed for life, died four years later, aged 77.

So, a decade on, there is an intense symmetry in the fact that Serge's son should now be representing some of the families of those Jewish Bordelais cravenly robbed of life. Yet Arno Klarsfeld, whose grandfather also died in Auschwitz, is careful to draw a distinction between the war crimes of the Nazis and that of the Vichy functionary, Papon. ''Future generations must know that those responsible for the 'final solution' in France were first and foremost the Germans who wanted to kill the Jews. Only after does responsibility lie with the Vichy administration which was indifferent to the fate of the Jews, but would not have done what it did had the Nazis not instructed it.''

to those who claim Papon is a scapegoat for France's bad conscience, that he is being tried because today there is no-one else, Klarsfeld spits out his disgust. This was a man, he says, who placed ambition before morals. ''The trial is important so that civil servants will never again blindly carry out orders just because they come from above.'' It escapes no-one that this particular chapter is ending just when Jean-Marie Le Pen's National Front seems to have shred the French right in last week's regional elections, his racism a virulent echo of the hatred which convulsed the world half a century ago. Does Klarsfeld perceive in that poison a revival of anti-Semitism?

''No, because the ultra-right is mostly concerned with striking against North African immigrants. But what is impressive is that, largely because of Jacques Chirac's stewardship, the various right-wing leaderships at national level seek no alliance with the extremists, even if it might be in their interests to do so.'' The best defence against Le Pen, he says, is a good economy. ''As long as there is no financial catastrophe in France, no further rise in unemployment, then Le Pen can be kept in check.''

Across the road from the nineteenth-century courthouse a hundred or so yellow placards are spread in a circle on the ground. Each bears a name in black, a star of David, and, in the right-hand corner, a photocopy of a specific deportation order: Alain GROSS. Born: 29.10.43. Domicile: 29 rue Henri IV, Bordeaux. Profession: nil. How could there be any profession? This citizen, who lived just streets away from the Palais de Justice, was only three months old. One of 223 children shunted out of France in convoys to Auschwitz when Papon was secretary-general of the prefect's office in the Bordeaux region, the supervisor of its wickedly coded Service for Jewish Questions. His signature on documents, which would eventually lead deportees to the gas chambers, is the most damning evidence, and once again it raises the question of how a cultivated man of respected intelligence could not have realised

- as he claims - the monstrous fate he was shaping for others. This was the bureaucrat who was twice described by the Nazis as a talented administrative specialist. ''Can be trusted,'' one report tersely observed. And after the war others clearly thought so too. For Papon was to serve France as budget minister.

Klarsfeld scoffs at the notion that Papon wept from grief that Christmas Day in 1943. ''Why would he cry if he didn't know those deportees were going on a lethal journey? When you are given so much education, when you come from a good family, and, yes, you love Mozart - in fact, when you have everything - how can you so easily send people to their death?'' But complicity builds slowly until it hardens over everything as an invisible scab. ''Little by little the crimes are committed,'' Klarsfeld muses. ''First you decide to join a government, the Vichy regime, which goes against everything you believed in the past. And then you no longer ask questions so as not to receive the answers. France, under Vichy, wanted its place in the new Europe which would be led by the Nazis, and Papon himself wanted his place in the sun.''

After all these months, what does he feel when he looks at this old man held together with mental agility and icy pride? ''My view is that he is someone who has always been very selfish, always sought to be on the side of power, which meant that, of his own free will, he chose to deny everything. He could have been the opposite, an outstanding example of what the brilliant and good civil servant should be.'' Then comes a sardonic reflection: ''Maybe, too, Papon has done a lot for octogenarians, the Fourth Age, by being so alert and in control.''

And Klarsfeld himself, the beau of coveted actresses and models, the brilliant law student turned reckless advocate, and author of two derided novels, what self-knowledge has he gained? In retrospect he thinks his whole life has been a preparation for Papon's trial, for even when he was a schoolboy his parents involved him in their work, although that meant he didn't really have a childhood. ''Perhaps that's why I still have this juvenile side, this need to skate everywhere at the age of 31.'' Yet if his court performance in Bordeaux does cost him dear among the legal hierarchy of France, he professes not to care. ''The people are for me, not

the notables. But it's like Rhett Butler in

Gone With The Wind: 'Frankly, my dear, I don't give a damn'.''

Except that's not precisely so. For all his harem-scarem strategy Arno Klarsfeld is profoundly committed to the purpose of this trial. He knows that the living cannot offer forgiveness on behalf of the dead, but gaining some understanding of what happened by excavating the truth provides a tremendously important lesson for the future. It ensures the vanished ones still matter, that they are not lost entirely.