Jerome Kerviel described his extreme trader past on the first day of his long-awaited trial as judges unpick his role in a 4.9 billion euro ($6.6 billion) trading loss that threatened to bring down Societe Generale.

The 33-year-old rogue trader, dressed in a dark suit, white shirt and a light-colored, thin-striped tie, spoke in a barely audible voice after the presiding judge asked him to tell the court about his background.

At certain times it was extreme ... Tiring, physically, Kerviel said as he described his job as trader at Societe Generale from 2005 after rising through the ranks of middle-office and assistant roles at the bank.

Kerviel told the hot, cramped courtroom in Paris's Palais de Justice that he worked from 7 a.m. to 10 p.m., bank holidays included, with only a brief break to eat a sandwich at his desk.

It was time-consuming. I lived to meet my targets, he said.

The encouragements of my superiors made me keep going, he told the court.

Kerviel, who could face five years in jail and a 375,000-euro fine if found guilty of charges of breach of trust, computer abuse and forgery, declared his current profession as consultant and his monthly salary as 2,300 euros.

Seated on a plastic chair in front of rows of lawyers in black garb, the ex-trader said his salary at Societe Generale was 48,000 euros in 2006 with an annual bonus of 60,000 euros.

The trial has drawn hundreds of journalists from around the globe. The presiding judge has banned the use of microblogging service Twitter inside the courtroom.

Kerviel is one of the most famous symbols of the financial crisis and his trial is seen as important for matters of future regulation and crisis prevention.

The trial will be watched closely around the world because it's a symbol of financial excess and what's going to be done about it, Bradley Simon, senior partner of law firm Simon & Partners LLP, which specializes in white-collar defense, said in a phone interview.

The trial also tests the ability of Societe Generale to cast the blame on Kerviel or whether his actions will be seen as a cultural flaw in our capitalistic system, Simon added.

Upon his arrival at court, Kerviel remained silent and allowed his lawyer, Olivier Metzner, to address the media scrum.

We hope that there will be transparency, that the truth will not be obstructed by Societe Generale, like it has been for two years, Metzner said.

Kerviel had been used as a pawn for profit and then thrown away, he said.

The trial will dredge up uncomfortable memories for Societe Generale as it tries to restore investor confidence in the midst of a fragile economic recovery and looming tighter regulation.

CHAIRMAN ABSENT

The bank's former chairman, Daniel Bouton, who was forced to step down last year in part due to the handling of the Kerviel scandal, has refused to appear in person at the trial, seeing his written testimony as sufficient, the presiding judge said.

Although Kerviel has admitted to building unauthorized trading positions leading up to the loss in 2008, he has said breaches in Societe Generale's risk control system were tolerated, and this has been a key part of his legal defense.

Societe Generale has hit back by saying he acted alone and that investigating magistrates had already dismissed his claims of tacit complicity from his bosses.

The bank said before the trial that it held Kerviel entirely responsible and called for exemplary punishment.

Facing off in the trial are two of Paris' best-known lawyers -- Metzner and Jean Veil.

Cigar-smoking barrister Metzner's clients include ex-Panama dictator Manuel Noriega, one-time Vivendi boss Jean-Marie Messier and former French Prime Minister Dominique de Villepin.

The trial is due to run until June 25, clashing with a crucial investor day for Societe Generale on June 15 as it tries to bolster confidence in its new strategy.

Analysts have said the bank's brand has suffered in the wake of the Kerviel scandal, allowing rival BNP Paribas to gain the advantage with domestic retail customers and, at the same time, forcing SocGen to cut down on proprietary trading.

($1=.7453 Euro)

(Additional reporting by Thierry Leveque and James Regan; editing by Karen Foster and Will Waterman)

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