Paris (AFP) - French far-right leader Marine Le Pen was on Tuesday questioned by judges probing her National Front (FN) party for fraud, according to sources close to the investigation.

Le Pen, 47, was questioned for several hours after twice previously having refused to appear before judges investigating the FN's finances.

The FN and several of the party's high-ranking members have been charged with misuse of company assets and conspiracy to commit fraud over the financing of parliamentary and presidential elections in 2012.

Financial investigators suspect the party's leaders and associated companies of defrauding the state by inflating campaign expenses.

The FN denies the embezzlement of millions of euros.

Le Pen is classified as an "assisted witness" in the French legal system, which means she herself is not formally under investigation but could still be charged.

Le Pen and her father, who founded the FN, have been dogged by legal woes, and recently attracted the attention of prosecutors who suspect they undervalued their assets in their tax declarations.

A French financial body, the High Authority for Transparency in Public Life, estimates both Le Pens underestimated their wealth by a third -- a figure of about one million euros ($1.1 million) for Jean-Marie and hundreds of thousands of euros for Marine.

The National Front won a record number of votes in regional elections in December, while failing to win any regions, as it continues its rise despite its legal woes and bitter internal battles.

Marine Le Pen, who is aiming to run in the 2017 presidential election, is also under investigation for tweeting graphic images of Islamic State atrocities, including the beheading of US reporter James Foley.

She has also been locked in a vicious feud with her father, who was booted out of the party earlier this year after rehashing familiar comments about Nazi gas chambers being a "detail" of history and saying France should improve ties with Russia to save the "white world".