Rogue trader Jerome Kerviel was in prison today after giving himself up to French authorities to begin a three-year prison term for his role in the near collapse of Société Générale bank.
The 37-year-old has spent the last two months on a walk from Rome to protest the "tyranny of the markets".
He was arrested by French police at midnight after crossing the Italian-French border at the Riviera town of Menton.
After an overnight stay in a police station there, he was transferred this morning to a prison in the nearby city of Nice.
The ex-trader brought one of Europe's biggest banks to the brink of bankruptcy in 2008 with wildly risky trades which resulted in a loss of €4.9 billion
Kerviel was convicted in 2010 of breach of trust, forgery and entering false data in relation to the unauthorised trades.
His conviction and three-year prison term were upheld in March but an appeal court overturned an order that he pay damages equivalent to the bank's losses.
Kerviel had been ordered to present himself at a French police station by Sunday at the latest in order to begin his prison term. He finally complied with the order having said at the weekend he would stay in Italy until he got a response to his request for President Francois Hollande to intervene in the case.
Kerviel said he would not seek a presidential pardon but had asked Hollande to grant immunity to potential witnesses who could testify in his favour.
He has said he wanted to detail to Hollande "the serious failings" that led to his conviction.
Kerviel has never denied taking on wild bets - at one point staking €50 billion of the bank's money - but maintains that his bosses were just as much at fault as he was.
The trader was earning a relatively modest €50,000 a year in basic salary when the scandal erupted in January 2008.