France’s Socialists are to join forces with the main opposition conservatives to prevent an electoral breakthrough by Front National leader Marine Le Pen.

Ms Le Pen, whose popularity is surging in the wake of the Paris attacks due to her strong stance on immigration, is standing for the presidency of the Nord-Pas-de-Calais-Picardie region, with many now viewing her as front-runner.

However, Socialist candidate Pierre de Saintignon said his party would withdraw from the race and back the candidate for the opposition Republicans.

“Madame Le Pen will not be president of the region because we will bear our responsibilities when the time comes,” he said. His party is expected to come third in this Sunday’s first round vote. If no party receives more than 50 per cent of the vote, a run-off will take place with all parties that receive more than 10 per cent qualifying.

The Times reports that Ms Le Pen has pulled ahead in the economically depressed northern region since Islamists murdered 130 people in Paris last month. Her party also stands a chance of taking power in neighbouring Normandy as well as the regions of Burgundy-Franche-Comté and Provence-Alps-Côte d’Azur.

If Ms Le Pen does win the regional presidency she will likely using it as a springboard for the French presidency in 2017.

Her niece, Marion Maréchal-Le Pen, 25, is standing in the Provence-Alps-Côte d’Azur region, where polls are predicting 45 per cent support, well ahead of the other parties.

Yesterday, the younger Le Pen insisted that Muslims could be considered French if they “bend to the mores and the way of life” inherited from France’s Christian heritage. She also strongly disapproves of her aunt’s acceptance of gay marriage.

France’s regional councils only hold limited responsibility – mainly dealing with school buildings, economic development and local train services – however, if Ms Le Pen wins it will show she can translate her support into winning office.