Cahuzac’s estranged wife Patricia admitted the existence of the Isle of Man account to authorities investigating her husband on charges of tax fraud, French newspaper Sud Ouest claimed.
Cahuzac, who in his role as budget minister was in charge of cracking down on tax cheats, was sacked in April last year after finally admitting that reports he had stashed €600,000 in a Swiss bank account were true.
But many sources close to the investigation suggested that the plastic surgeon had actually tried to keep a much larger sum of money away from the French tax man.
Le Parisien newspaper said sources in Switzerland claimed Cahuzac had actually tried to hide as much as much €15 million.
The hunt to track down the ex-minister’s money led investigators to the Isle of Man, where an account containing the equivalent of around €2.5 million was opened between 1997 and 2004, Sud Ouest claimed on Thursday.
The funds were then invested in the UK property market, Patricia Cahuzac is alleged to have told investigators, who are reportedly set to visit to London to try to verify her testimony.
Patricia Cahuzac was herself charged last August on for tax fraud and laundering the proceeds of tax fraud as part of the probe into her husband.
Cahuzac, who had initially refuted the allegations, describing them as "crazy", eventually issued an apology and said he was 'devastated by guilt'.
The minister, who faces five years in prison and a fine of up to €375,000 said he had been "caught up in a spiral of lies and lost his way."