Le Pen's National Front set to top poll in France's first elections since Paris attacks

They projected that the National Front won between 27% and 30% of support in the voting, followed by former president Nicolas Sarkozy's Republicans party and President Francois Hollande's governing Socialists.

The elections took place in an unusually tense security climate, expected to favour conservative and far right candidates and strike a new blow against the Socialists.

While National Front had significant support, the party may not be able to translate that into victory in the second-round voting on December 13 for leadership of France's 13 newly-drawn regions.

Mr Sarkozy's Republicans party and its allies were projected to come in second place at around 27%.

The Socialists, who currently run nearly all of the country's regions, are projected to come in a weak third place, with between 22 and 24%.

The Paris attacks on November 13 that killed 130 people and a Europe-wide migrant crisis this year have shaken up France's political landscape.

The National Front's leader, Marine Le Pen, is hoping the two-round voting that started on Sunday will consolidate political gains she has made in recent years - and strengthen the party's legitimacy as she prepares to seek the presidency in 2017.

The unpopular Mr Hollande has seen his approval ratings jump since the Paris attacks, as he intensified French air strikes on the so-called 'Islamic State' group targets in Syria and Iraq and ordered a state of emergency at home.

But his party, which currently runs nearly all of France's regions, has seen its electoral support shrivel as the government has failed to shrink 10% joblessness or invigorate the economy.

Many political leaders are urging apathetic voters to cast ballots as a riposte to fundamentalists targeting democracies from France to the US.

First-time voter Eli Hodara, an 18-year-old Paris student, expressed hope that more young people would turn out.

"I think it is important to vote even if one leaves the ballot blank," he said.

It is the last election before France votes for president in 2017, and a gauge of the country's political direction.

"It's an important moment, important for the future of our regions, important also for the future of our country, important with regard to the catastrophic and dramatic events that have hit France," Ms Le Pen said as she cast her ballot in the northern city of Henin-Beaumont.

The arrival of hundreds of thousands of migrants in Europe and the exploits of 'IS', which has claimed responsibility for the Paris attacks, have bolstered the discourse of the National Front.

It denounces Europe's open borders, what it calls the "migratory submersion" and what it claims is the corrupting influence of Islam on French civilisation.

Ms Le Pen is campaigning to run the northern Nord-Pas-de-Calais-Picardie, which includes the port city of Calais, a flashpoint in Europe's migrant drama. Polls suggest she could win.

Her young niece, Marion Marechal-Le Pen, appears to be on even stronger footing in her race to lead the southern Provence-Alpes-Cote d'Azur region, including the French Riviera and part of the Alps.

A win for either would be unprecedented in France.

The party was long a pariah, and voters left and right joined together to keep Marine's father Jean-Marie Le Pen from winning a presidential run-off in 2002.

However, Marine Le Pen has worked to undo its image as an anti-Semitic party under his reign and has lured in new followers from the left, the traditional right and among young people.

Socialist Prime Minister Manuel Valls and the conservative-leaning national business lobby issued a public appeal this week to stop the National Front's march towards victory.