The 48-year-old former lawyer has spent years trying to broaden support for her National Front party, but she has signalled a return to the core concerns of many of her supporters in recent speeches.
Speaking on BFM television on Wednesday, Le Pen emphasised how she would pull France out of the European Union, slash immigration, make it harder to get French nationality and crack down on suspected Islamists.
"French people have the feeling of being dispossessed of their identity, of their social security system and their sovereignty," Le Pen told the channel.
Polls show a four-way race developing ahead of the first round of the election on Sunday between Le Pen, 39-year-old centrist Emmanuel Macron, conservative Francois Fillon and far-left firebrand Jean-Luc Melenchon.
Two of them are expected to advance to a run-off vote on May 7.
After a string of Islamist-inspired assaults in France since 2015, security concerns moved to the centre of the campaign Tuesday following the arrests of two French men suspected of preparing an attack to disrupt the election.
Le Pen has proposed expelling any foreigner convicted of a crime or suspected of being radicalised. Convicted extremists with dual nationality would also be stripped of their French passports.
"The measures that I want to put in place would mean that many of these people (Islamist attackers) would not have been on our territory or living freely," she told BFM, repeating a claim from a speech on Sunday night.
French voters have so far been more concerned about unemployment and their spending power than terrorism or security, polls show, though analysts warn this would change quickly in the event of violence.