Jerome Kerviel has been found guilty of forgery, breach of trust and unauthorised computer use by a Paris court in relation to 2008's EUR4.9 billion rogue trading loss at Société Général.
The former trader has been sentenced to five years in jail, two of them suspended, and ordered to repay the bank the entire EUR4.9 billion.
Kerviel admitted lying to colleagues, falsifying documents and entering fake trades when he stood trial in in June over the trading losses, which came to light in 2008.
However, the 'rogue trader' insisted that his actions were common practice at the bank and bosses turned a blind eye.
According to CNN, Kerviel's lawyer, Olivier Metzner, called the verdict "unreasonable" and plans to appeal within the allotted 10 days.