French prosecutors said on Tuesday they would examine allegations that far-right patriarch Jean-Marie Le Pen hid
money in a secret account in Switzerland.
The claims come amid a bitter feud between Le Pen and his daughter Marine, who now leads the party, which has been facing a string of investigations into campaign funding both by French and European authorities.
Le Pen "kept a hidden account at HSBC, as well as the (private Swiss) CBH bank through a trust placed under the legal responsibility of his butler, Gerald Gerin," the investigative website said.
"Of the €2.2 million placed in the trust account, 1.7 million were kept as gold bars and coins," it added.
"Prosecutors in Nanterre (west of Paris) received this information from the anti-money laundering unit Tracfin," Mediapart said.
Contacted by AFP, neither CBH nor HSBC would comment on the report. Le Pen also refused to comment, while FN Vice President Florian Philippot told French TV channel iTELE he knew nothing about the claim.
"I don't know whether it's true, but knowing Jean-Marie Le Pen, I would find it strange if it were," Philippot said.
"I've spoken to Marine Le Pen on the phone. She is very surprised and doesn't know anything about it either. Like the rest of us, she is waiting for Jean-Marie Le Pen to clarify and explain," he added.
Tracfin, an intelligence service that investigates money laundering among other crimes notified prosecutors in the Paris suburb of Nanterre with their suspicions on Monday.
"This notification is going to be examined by prosecutor Catherine Denis and the financial division to decide whether to pursue judicial action," the prosecutor's office said.
Asked about the allegations, Le Pen on Tuesday blasted a "general offensive against" the far-right party.
"I do not need to explain myself over what anyone says, particularly parapolice bodies tasked with sowing disruption in the political class," he told France Inter radio.
In 2013, the former paratrooper admitted he kept an account in Switzerland at UBS that he had opened in 1981.
The longtime FN leader and current European parliament member has been under investigation since late 2013 over undeclared assets estimated at €1.1 million.
A separate probe also underway focuses on the FN's campaign financing since Marine Le Pen's takeover -- with five people and the events company Riwal already charged -- while the party has also been referred to the EU's anti-corruption agency.
The party has also denied taking money from Russian leader Vladimir Putin in return for support for the Kremlin strongman, but recently received a €9 million loan ($9.8 million) from the Czech Russian Bank.
The elder Le Pen recently repeated his claim that Nazi gas chambers were merely a "detail of history", comments that have seen him convicted in the past for denying the Holocaust.
Marine Le Pen distanced himself her father after his latest outbursts, saying he had committed "political suicide".
Under pressure from his daughter, the elder Le Pen then gave up his bid to run in a regional vote, though he had vowed not to go quietly.
He was replaced by his 25-year-old granddaughter, Marion Marechal Le Pen.
The anti-immigration NF, which under Marine Le Pen is trying to clean up its racist image, wants France to withdraw from the European Union, pull out of the euro and reintroduce the franc.
It has made a series of major gains in recent elections, topping the poll in the European election in May 2014.