A building housing French presidential candidate Marine Le Pen's campaign headquarters was hit by a arson attempt on Thursday, firefighters and police said, with only minor damage caused.
Firefighters were called around 2:40 am (0040 GMT) to the ground floor offices of an insurance company on the upmarket Rue du Faubourg Saint-Honore in central Paris.
A fire service spokesman said the fire was "quickly brought under control" and damaged only the door and a doormat.
The upper floors of the building, on one of the French capital's most exclusive streets close to the president's Elysee Palace official residence, house the campaign offices of far-right National Front (FN) leader Le Pen.
The anti-globalisation, anti-EU Le Pen is neck-and-neck with centrist Emmanuel Macron in polls for the first round of the election on April 23.
A police source said the cause of the fire was "not natural and probably criminal", adding that the graffiti slogan "FN vs KLX" was found nearby.
A group calling itself "Fight Xenophobia" contacted AFP to claim the attack, which it said was carried out with "Molotov cocktails".
The caller, who refused to give a name, also claimed to have carried out a similar attack on a far-right newspaper and said the action would continue until the election.