She took time off after losing the second round of the presidential election on May 7 to Emmanuel Macron.
Le Pen confirmed on Thursday night that she would stand as a candidate in the June elections for the northern former coal mining town of Henin-Beaumont, in her first public comments in nearly two weeks.
She took time off after losing the second round of the presidential election on May 7 to Emmanuel Macron with a score of 33.9 percent -- disappointing compared with her target but still a record 10.6 million votes for the FN.
Since then, the party has publicly raked over the reasons for the defeat and split over its key policy of wanting to scrap the euro -- seen as too risky by many voters, particularly from the older generation.
"The analysis of the presidential campaign and thinking about our positions in detail, that's a focus for after the parliamentary elections," Le Pen told a press conference on Friday in Henin-Beaumont.
"The priority, unique and essential focus is the focus on the fight for the parliamentary elections," Le Pen added, saying she hoped for as "many lawmakers as possible" in the National Assembly.
She stressed again that the National Front was the main opposition to Macron's presidency, repeating her belief that the key split in French politics was now between her "nationalists" and Macron's "internationalists."
This was a re-run of her argument during the presidential election when she regularly assailed Macron as a candidate of international finance, the European Union, open borders and unfettered globalisation.
While the FN has never been so popular nationally measured by its vote share, Le Pen's comments hint at the squabbling and sharp ideological differences that have burst into the open since her presidential defeat.
Her hardline and popular niece Marion Marechal-Le Pen has decided to quit frontline politics for a career in the private sector. The social conservative is one of only two sitting MPs in the national parliament.
And Le Pen's top aide and strategist Florian Philippot has also warned he will quit if Le Pen listens to several rival heavyweights and abandons the party's pledge to scrap the euro.
In a sign of his ambitions, Philippot launched his own political movement on Monday called "The Patriots". His assurances that it would be under the FN's umbrella did not convince critics.
"In the current context it would be better to create an association to win the parliamentary elections," senior FN figure Gilbert Collard wrote in Le Figaro newspaper on Wednesday.
In her interview on Thursday, Le Pen acknowledged that her euro stance during the presidential election had scared off some voters.
"The subject of the euro worries French people considerably, in an almost irrational way," said Le Pen. "We are going to have to take this into account, discuss and reflect."
She also said that she had performed poorly in a head-to-head debate against Macron on May 3 in which her strategy seemed to be to attack her opponent as aggressively as possible.
"I wanted to make clear the very large fears I had with regard to Emmanuel Macron. I did it with fire, passion, perhaps too much fire, too much passion," she said. "Some people weren't expecting it."
Pro-European centrist Macron, who was visiting French troops active in west Africa on Friday, is hoping to secure a majority in the parliamentary elections to push through his ambitious reform agenda.