Marine Le Pen, the leader of France's far-right Front National, is expected to face charges for incitement to racial hatred in France, after the European parliament voted to lift her parliamentary immunity.

The French state prosecutor in Lyon had asked the European parliament to lift Le Pen's protection from prosecution as an MEP so she could face charges over a speech in 2010 in which she likened Muslim street prayers to the Nazi occupation of France.

The case threatens to upset Le Pen's careful public relations strategy since taking over the party from her father, Jean-Marie Le Pen. She had sought to project a modern, more palatable face of the far-right in France, free from the type of comments about the second world war and Holocaust denial that have seen her father convicted in court.

Last year, Le Pen Sr was convicted of contesting crimes against humanity for saying the Nazi occupation was not "particularly inhumane".

Marine Le Pen, who has been an MEP since 2004, this week called herself a dissident who was being pursued for political reasons for a "crime of opinion" and said she stood by her comments.

In December 2010, during her party's internal leadership campaign, she made a speech in Lyon that denounced Muslims holding prayers in the streets – at a time when a lack of mosques in France had forced many to pray outside. She likened the outside prayers to an occupation and added: "For those who like to talk about world war two, to talk about occupation, we could talk about, for once, the occupation of our territory. There are no armoured vehicles, no soldiers, but it is an occupation all the same."

On Monday on French TV she repeated her comments, saying she was being targeted "for having dared to say what all French people think, that street prayers – which I must add continue to happen on French territory – are an occupation". But she did not explicitly evoke the second world war parallel.

The Front National is currently at a high in the opinion polls, after a high score in a byelection in Villeneuve-sur-Lot in south-west France, where the party knocked out the Socialists and scored 46% of the vote in the final round.

A recent poll for YouGov about voting intentions in the European parliament elections next year put the Front National one point behind the traditional rightwing UMP, and ahead of the Socialist party. © Guardian News and Media 2013