At a final rally, Le Pen underscored the national character of the regional vote, telling cheering supporters that a new France is within their grasp and inside the ballot box.
The lead candidates in all 13 French regions contesting the presidency of leadership councils shared the stage with Le Pen.
The anti-immigration National Front led in six regions in the December 6 first round, and Le Pen herself led by a wide margin in the north where she is running.
Such an outcome would be a major setback for the National Front and for Marine Le Pen's planned bid for the presidency in 2017.
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The two Le Pens scored so well in round one that the governing Socialists, straggling in third place, ordered their candidates to withdraw so their voters could cast ballots for the rival conservative mainstream to block the far right.
Le Pen softened her usually trenchant stance in a reach-out to left and right, saying her party represents a new way where "patriots" respect the interests of the regions and clans and "political fraud" have no place.
But she also said that National Front regions would "open each file" when deciding on subsidies for associations and other interests and "stop, reform or continue."
She and her niece have said in the past that they would refuse funding to interests representing a single community, a reference to Muslim groups. Both regions have large Muslim populations.
Earlier yesterday, Le Pen vowed, if elected to head the north, to bring suit against the French state over the situation in Calais, where thousands of migrants are camped in hopes of reaching Britain.
The poll of voter intentions suggested Marine Le Pen would get 47 percent and her conservative adversary Xavier Bertrand, a former labour minister, 53 per cent.