Bannon's appearance in France was part of a European tour as he seeks an global platform for his closed-borders, anti-foreigner message.
The one-time White House strategist, who is often credited with helping Donald Trump win the presidency in 2016, told the group, "The tide of history is with us, and it will compel us to victory after victory after victory", The Washington Post reported.
Bannon, an American nationalist who ran the right-wing Breitbart News, was among Trump's closest aides during the 2016 United States election campaign, the presidential transition and his first months in office. Let them call you nativists. "Wear it as a badge of honor". Le Pen and her allies are also expected to announce a new name for the party that they hope will appeal to more voters in the future.
Last week, Bannon appeared in Rome to observe the elections and advocated for an alliance between the anti-immigrant League party and the populist Five Star Movement in Italy.
The speech will be the second in Europe for Mr Bannon who recently spoke to a sold-out arena in Zurich, Switzerland where he spoke on the subject of on populism of the left and the right. "And history is on our side", he said.
He praised Le Pen's vision of a political spectrum that no longer spans left-right but puts nationalists versus globalists.
Bannon had faced mounting pressure after he was quoted disparaging President Trump and his family in Michael Wolff's book, "Fire and Fury: Inside the Trump White House".
Le Pen told French television on Friday that a name change was needed to show the FN had grown up and become "adult".
She has long sought to "de-demonize" the party by moving away from its racist past, but Le Pen's own father complained that Bannon was the "most radical" of Trump's advisers, saying Saturday's invitation "is not exactly the definition of 'de-demonization'". She bowed out of politics after her aunt's presidential defeat, but is expected to come back in a new role.
The congress would mark a significant break with Le Pen's father, Jean-Marie Le Pen, who founded the National Front in 1972 and has called a name change a "betrayal".
Party members supported legalised euthanasia, which Le Pen opposes, favour of gay marriage and are against the death penalty, she said.
The changes pave the way for a younger leadership circle to emerge, even if the party's ideological foundation remains unchanged: nationalist, identity-driven, anti-European Union, according to Jean-Yves Camus, an expert on the far-right.
The party conference in Lille will also feature a vote as to whether the elder Le Pen can keep his title as the party's honorary president.