The campaign headquarters of French presidential hopeful Marine Le Pen were attacked on 13 April, in suspected reaction against the Front National party leader's controversial comments about the Holocaust she made a few days previously.

According to the police, a Molotov cocktail was thrown at the Rue du Faubourg Saint-Honore building in central Paris, damaging a door and doormat. The arsonists also left the graffiti tag "FN vs KLX" on the wall of the premises. The message referred to Le Pen's National Front and a group called Kombattre La Xénophobie (Fight Xenophobia).

AFP confirmed that Kombattre La Xénophobie contacted the agency to claim responsibility for the attack and said that they had carried out a similar attack on a far-right newspaper. The unidentified caller said the group would continue attacks up until the election.

The FN offices are located on a higher floor of the building and the ground floor offices of an insurance company were the ones affected. Firefighters were called around 2.40am to on the upmarket in central Paris.

A spokesman for the fire department said the fire was "quickly brought under control".

Le Pen accused a leftist group of carrying out the attack and said she would file charges.

"I assume this is due to a small leftist group," she told France 2 television. "These groups act in total impunity," she said, adding that the government needed to dissolve them.

French Interior Minister Matthias Fekl condemned the attack and said that security would be strengthened in the party called for it. "These are unacceptable acts, the democratic debate must take place in the ballot box," he told RTL radio.

It is suspected that Le Pen's recent Holocaust comments may have triggered the KLX attack. Speaking to RTL radio, the presidential race frontrunner denied France's involvement in the 1942 round-up of 13,000 Jews in the Paris region who were then sent to Nazi concentration camps.