Gilbert Chikli, 49, who fled to Israel in 2009 after being charged, was the mastermind of a scheme which saw him fleece some of France's top companies, and is the subject of an international arrest warrant.
During the trial, a former director of the Credit Lyonnais bank -- now known as LCL -- gave the court a run down of Chikli's scheme that convinced her to hand one million euros to a stranger in the bathroom of a Parisian bar.
First, a man introducing himself as the president of Credit Lyonnais called her and told her a secret services agent would shortly get hold of her and she should do everything he told her.
The agent explained he was working on a case involving money laundering and terrorism and needed her to transfer him money to dismantle a criminal network.
"He spoke about attacks, confidentiality, he isolates you. At the time I was under pressure at work and I wanted to do things properly," she told the court.
Among the 33 banks and businesses targeted with the scheme between 2005 and 2006 were consulting group Accenture, which lost 5.9 million euros, the Post Office Bank, HSBC, aerospace firm Dassault, electricity and rail giant Alstom and chic Parisian department store Galeries Lafayette.
Some of the affected banks and companies that filed a civil suit were awarded €5.5 million ($6.1 million) in damages and interest.
Two of the fourteen alleged accomplices involved in the trial were acquitted, while the others received fines or jail terms of up to four years in jail.
- 'Gift of the gab' -
Prosecutor Alice Cherif said Chikli used mental manipulation and harassment to wear down carefully chosen targets.
The technique "combines validation: 'I chose you for the mission' ... and isolation: 'don't tell your colleagues, your family," said the magistrate.
The prosecutor said most of the 52 employees who were duped at the various companies had been fired.
Chikli managed to swindle a total of 60.5 million euros, 52.6 million euros of which was later recovered.
His story inspired a movie that is currently being filmed.
In 2010 he proudly told French television he was not a crook and that his scheme was a "game."
"We contact businesses, banks, we pretend to be their president and with a rather extraordinary gift of the gab we manage to get large amounts of money.
"Either you have the gift or you don't. You could say I have the gift."
The prosecutor said Chikli pioneered a hoax which had been adopted by copycat fraudsters and become a "scourge" in France, with 710 such cons worth 365 million euros having taken place since 2010, and nearly 1,000 others foiled.