But results from the second round of regional elections showed the party didn't get enough votes to shift the balance of power.
National Front leader Marine Le Pen had garnered just 45.43% of votes in Nord-Pas-de-Calais-Picardie, according to early official results from the Interior Ministry
. Xavier Bertrand, candidate of the mainstream center-to-right alliance, has won 54.57% of the votes. Nord-Pas-de-Calais-Picardie borders Belgium and the English Channel.
In the southern Provence-Alpes-Cote d'Azur, Le Pen's niece, Marion Marechal-Le Pen, was also trailing her rival, Christian Estrosi. According to official results, Marechal-Le Pen has garnered 48.85% of votes and Estrosi has won 51.15%.
The anti-immigration National Front sent shock waves through France's political establishment when it emerged as the leader after the first round of voting last weekend
, capitalizing on security concerns in the wake of last month's deadly Paris terror attacks
Le Pen seemed unfazed by the second round results, vowing that her party's fight for France was just beginning and that she'd be back on the ballot in the 2017 presidential elections.
"Nothing will be able to stop us," she said on Twitter
Candidates withdrew to block National Front victory
In the first round of voting, the National Front led in six of France's 13 regions, edging former President Nicolas Sarkozy's conservative Les Republicains party into second place nationally. President Francois Hollande's ruling Socialist party came third.
Parties that got more than 10% of the vote were eligible to participate in the second round of voting.
Newspapers across the political spectrum reacted with shock to the National Front's strong showing in the first round, which Le Pen said indicated that the National Front was now "the first party of France."
In a bid to keep the National Front from gaining power, the Socialists withdrew candidates who were trailing in key regions to avoid splitting the anti-National Front vote. They urged their supporters in those seats to give their votes to Les Republicains instead.
It was a successful strategy, CNN contributor Stefan de Vries said.
"The government appealed to the left-wing voters to vote for a right-wing candidate in order to basically ... make it impossible for Marine Le Pen to win any region. And it seems that their strategy has worked," he said.
But that doesn't mean the regional elections weren't a victory for Le Pen, he said, whose party has traditionally been seen as outside the political mainstream.
With 98% of ballots from the second round counted, the National Front had won more than 6.8 million votes, a record high for the far-right party.
"Her results this week show that she has a huge springboard for the 2017 elections," de Vries said. "She can continue her strategy to tell the French people, 'I am the victim. You are being taken hostage by the elitist traditional parties.' ... The French National Front is now really part of the French political system, which was, until recently, a bipartisan system just like in the United States."
Voting in shadow of Paris attacks
The regional elections were the first to be held in France under a state of emergency imposed in response to last month's deadly attacks by Islamist radicals in Paris.
ISIS claimed responsibility for the attacks. In response, Hollande vowed to destroy the terror group and set about strengthening international efforts to wage a military campaign targeting ISIS territory in Syria and Iraq.
The rise of attacks by Islamist terrorists, combined with the migrant crisis that has seen hundreds of thousands of mostly Muslim immigrants cross into Europe, has fed support for the National Front's anti-immigration policies.
Le Pen told CNN's Hala Gorani in the wake of the Paris atrocities that Europe's acceptance of migrants on such a scale was "crazy."
"I had also warned ... the authorities very clearly that there will be in these immigrants terrorists, who will infiltrate ... and that's exactly what has happened," she said.
"Given this kind of huge threat, which is literally a declaration of war to France, we cannot take the risk."
The National Front came in third after the second round of voting in the previous regional elections in 2010, and third in the most recent legislative elections in 2012
, earning the party two seats in the National Assembly.
In May last year, the party had unprecedented success in France's European elections
, winning 25.41% of the vote -- enough for 23 seats in the European Parliament.