The 48-year-old former lawyer has spent years trying to broaden support for her National Front party.
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.
The two arrested suspects, who were found in Marseille with a cache of weapons and explosives, were being questioned in the southern city on Wednesday where Le Pen is set to appear later at a rally.
Left-leaning Le Monde newspaper warned that Le Pen's claim that she would have prevented attacks that have claimed hundreds of lives was "absurd".
"You don't seek votes on the backs of dead people. It's a sort of moral red line," the newspaper said.
Some analysts have also depicted the French election as a sort of referendum on the European Union, with Le Pen proposing to pull France out of the 28-member club and scrap the euro common currency.
On Tuesday night, she insisted that the TF1 television channel remove the blue-and-yellow European flag from behind her before an interview.
But Melenchon, her eurosceptic far-left opponent, sought to soften his position on Tuesday night, stating that he did not seek to end the European Union or the euro despite criticising the "ultra-liberal" trading bloc for years.
"Don't believe what they tell you, 'He wants to leave Europe, the euro'... let's be serious," he told supporters on Tuesday night.
The Communist-backed candidate has pledged to renegotiate some of the founding treaties of the bloc, however, which would cast serious doubt on the viability of the postwar project of integrating the continent.
Polls show that a majority of French people still support the EU and the euro.
Veteran centrist Francois Bayrou, who has backed Macron, warned Wednesday that several possibilities were possible for the run-off vote on May 7.
The election has been one of the most unpredictable in decades and takes place against a backdrop of rising rightwing nationalism, seen most notably in Britain's decision to leave the EU and Donald Trump's presidential victory in the United States.
"A second round Melenchon-Le Pen, it's terrifying for the country, for the image of the country and for its future, because the choices proposed are extremely risky," Bayrou said.