Paris police say a gasoline bomb hit the building housing French far-right presidential candidate Marine Le Pen's campaign headquarters, causing a small fire.

The Paris fire department says no one was injured in the incident overnight Thursday and the blaze was quickly extinguished. The device hit an insurance office on the ground floor where Le Pen's campaign is based.

An investigation is underway. Police say vandals also scrawled graffiti targeting Le Pen's anti-immigration National Front party.

Le Pen said on France-2 television Thursday that she suspects extreme-left activists in the incident, but said that her campaign has not been contacted by investigators.

Le Pen is a leading contender for France's presidential election, held in two rounds April 23 and May 7.