Voters in France’s eastern Doubs department cast their ballots in a by-election second round that could add to the racist National Front’s (FN) total of National Assembly deputies.

FN candidate Sophie Montrel, who has campaigned against the “Islamic peril” in France, led on 36 per cent in the first round against 32 per cent for her Socialist Party opponent Frederic Barbier.

While Mr Barbier has been backed by communists and other leftwingers in the second round, he will also need votes from UMP conservatives to win.

Ms Montrel, who has previously spoken of “the evident inequality of races,” is hoping to capitalise on efforts by FN leader Marine le Pen to present herself as less extreme than her father Jean-Marie le Pen, who founded the far-right outfit.

Mr Barbier has based his campaign on the spirit of national unity that followed the murderous attacks on the Charlie Hebdo magazine and a kosher supermarket.