There was a sense of urgency in the voice of the man claiming to be France's defence minister, Jean-Yves Le Drian.

"We're talking about the lives of French citizens and we would like to free them. If we don't, we expect the worst," the man said in an audio recording of a telephone solicitation obtained by CNN.

"I need to know if you can join us in this mission so we can carry it out and if the answer is 'yes' then I will alert the presidency to say we have someone who can act as a mediator for us."

On the receiving end of the telephone line was Olivier de Boisset, a Frenchman who heads an IT company in Niger.

De Boisset was being asked to wire over 2 million dollars to allegedly help free French hostages being held by terrorists in Mali.

The voice said France needed de Boisset's help transferring funds because officially the country does not pay ransoms and gave assurances that France's central bank would reimburse him.

Many high-profile individuals were duped by the scammers.

De Boisset was suspicious, but he could never have imagined the extent of the scam that was being played on him.

Not only were there no French hostages in Mali, but he had just become the latest victim in a multi-million dollar con that would span two years and target more than 150 people including the spiritual leader Aga Khan, the President of Niger, the Prime Minister of Norway, the Archbishop of Lyon, the owner of Chateau Margaux wines, the King of Belgium, the director general of UNESCO and numerous CEOs.

Attempts to extort money from embassies and governments were made in more than 50 countries, according to French court documents.

CNN has obtained exclusive recordings made by often-skeptical victims showing how a group of fraudsters tried to pull off what some in France are calling the scam of the century by impersonating France's then defense minister, Jean-Yves Le Drian, and conning wealthy individuals out of 80 million euros purportedly to help pay ransoms to free French hostages being held by Islamist terrorists.

Some of the money has not been recovered.

Six of the alleged fraudsters are currently on trial in Paris in connection with the Le Drian hoax and a plot to impersonate Prince Albert II of Monaco while a seventh defendant is on trial only for the Albert of Monaco plot.

The con was elaborate

According to many of the victims, to earn their trust an initial phone call was followed up by a Skype video call. During this exchange, the con artist wore a custom-made silicone mask of Le Drian's face and sat in a replica of the minister's office complete with both the tricolor flag of France and a flag of Europe, pictures in the court documents show.

Another one of those targeted in June 2016 by the bogus Le Drian was Bruno Paillard, who heads a champagne house in Reims, northern France.

Paillard told CNN the hustle was impressive because of its elaborate nature. "The image was not very precise and the voice was a little bit strange. The excuse was that they were in a bunker in the ministry," Paillard said.

In addition to the Skype calls, Paillard said they communicated with him on official-looking letterheads from the ministry, but despite all their efforts Paillard said he wasn't convinced and went straight to the police.

"As a champagne producer we make people happy, but we're not necessarily good at saving the lives of people who are being held in strange countries," Paillard told CNN.

Paillard said the fake Le Drian had done his homework, he even knew how many children he had.

Wine maker Guy-Petrus Lignac was equally astonished at how much the fraudsters knew about him. He said they drew on his background to appeal to his sense of patriotism.

"They knew so many things about me! That I had been a police officer in the past. That's not common knowledge, it's not on the internet. I was surprised," Lignac told CNN.

Many of the victims were skeptical and went to the defense ministry to report the calls. The ministry alerted investigators in the summer of 2015 and an investigation was opened in April 2016, according to court documents.

Lawyers for Le Drian said French embassies all over the world were warned of the scam in 2016. However, the ministry didn't see the need for a press conference. (CNN)

Update news