The main groups in the EU Parliament decided they would change the rules in order to keep Le Pen from taking on the honorary role of presiding over the European Parliament's opening session this summer.

Joseph Daul, head of the European People's Party -- the biggest grouping in the parliament -- said he would "do everything possible" to prevent Le Pen from taking the chair. Daul is backed by socialists and the Greens in parliament.

Le Pen insists he's the victim of "inflammatory accusations" by the parliamentary socialist group head, German European MP Martin Schulz, who had branded him a Holocaust denier.

"I just said that the gas chambers were a detail of Second World War history, which is clear," he told a sitting of the European Parliament in Strasbourg, France on Wednesday, March 25.

Some six million Jews were killed during the Holocaust.

Past convictions for racism

Le Pen, 80, has several past convictions for racism and anti-Semitism. He shocked Europe in 2002 when he placed second in the French presidential elections. He won 10 percent of votes in the 2007 presidential race.

Back in 1987, Le Pen was fined 1.2 million francs (185,000 euros, $290,000) for making remarks downplaying the Holocaust in a radio interview.

"That proved the state we find the freedom of speech in Europe and France," he said, recalling the case.

Parliament's most senior member

Le Pen was first elected to the European Parliament in 1984. If he is elected at the top of the National Front ticket, he would be granted the honor of presiding over the opening session of parliament due to his seniority and age.

"I am concerned by the fact that a Holocaust denier could preside over the opening session of the European Parliament," Schulz had said previously.

Le Pen demanded an apology from Schulz on Wednesday.