Skirmishes broke out on Saturday ahead of a campaign rally by French far-right leader Marine Le Pen, prompting the removal of more than a dozen protesters and the evacuation of the hall in Ajaccio, Corsica.

The latest polls ahead of the April-May, two-round presidential election show Le Pen - leader of the anti-immigrant National Front - neck-and-neck with centrist Emmanuel Macron, who is expected to beat her in the runoff.

Polls also show that right behind them, far-left veteran Jean-Luc Melenchon has risen rapidly in opinion polls after his performance in a televised debate early this week, drawing level with conservative candidate Francois Fillon, whose presidential bid has been tainted by corruption charges.

Around 50 Corsica nationalists demonstrated in front of the venue in Ajaccio where Le Pen was holding her rally, chanting "We do not want the National Front", according to local newspaper Corse Matin.

Some of them managed to enter the hall where Le Pen was expected to speak. They clashed with Le Pen's security team, throwing punches and firing teargas, prompting the evacuation of the hall, the newspaper said.

A Corsican nationalist movement claimed responsibility for incidents.

"We will never let this party, whose former leader had demanded the death penalty for Corsican political prisoners, come safely to our country," the organisation A Ghjuventù Independentista, said in a statement, referring to Marine's father Jean-Marie Le Pen.

The campaign event was delayed for an hour and moved to another venue, French television BFM TV said.

Le Pen's campaign manager David Rachline said on twitter that local authorities had not done enough to secure the venue and had allowed far-left "militia" to come too close.

Rachline said a National Front activist was seriously injured during the clashes.

In her stump speech, Le Pen assailed her rivals Macron and Fillon on immigration, security, and ties to the European Union, while making local promises to the Corsican electorate.