The revelation comes just nine days before France heads to the polls for a highly-unpredictable presidential election with Le Pen, who heads the eurosceptic Front National (FN), one of the frontrunners in the April 23 first round.

The demand was made at the end of last month after she invoked her parliamentary immunity in refusing to attend questioning by investigating magistrates on March 10.

The case is linked to an expenses inquiry in which the European Parliament has accused Le Pen's FN of defrauding it to the tune of some 340,000 euros ($360,000).

The parliament believes the party used funds allotted for parliamentary assistants to pay Le Pen's personal assistant Catherine Griset and her bodyguard Thierry Legier for party work in France.

French investigators leading the case raided the party's headquarters outside Paris last month in a bid to determine whether the FN used European funds to pay for 20 assistants -- presented as parliamentary aides -- who were working for the party elsewhere.

But Le Pen shrugged off the request, saying it was "normal".

"It's totally normal procedure, I'm not surprised," she told Franceinfo radio.