She's not on the ballots, but Marine Le Pen is the focus of elections for more than 2,000 councils across France.

Opinion polls rate Le Pen's National Front Party the favorite versus the ruling Socialists and conservatives ahead of Sunday's vote. The result could prove crucial in building Le Pen's grass-roots base if, as expected, she runs for president in 2017.

The National Front's opposition to immigration, radical Islam, the European Union and the euro has helped transform the party from a pariah under Le Pen's father.

France's council elections are in two rounds, so victory Sunday will determine which candidates can contest a second vote March 29.

Candidates appear on ballots in pairs — one male, one female — to ensure that 50 percent of council members are women.