Early polling predicts leftist coalition has won the most seats in ...

Polls have closed in France, with projections saying a coalition on the left that came together unexpectedly has won the most parliamentary seats in the pivotal run-off elections.

The surprise projections put President Emmanuel Macron's centrist alliance in second and the far right in third. 

The far-right National Rally drastically increased the number of seats it holds in the parliament, but fell far short of expectations.

Final results are not expected until late Sunday or early Monday local time in the snap election that was called just four weeks ago in a huge gamble for Mr Macron. 

People react at the Place de la Republique in Paris after partial results in the election came out over the weekend.(Reuters: Abdul Saboor)

The deeply unpopular president has lost control of parliament, according to the projections. 

But the lack of majority for any single alliance has plunged France into political and economic turmoil.

The country now faces the prospect of weeks of political machinations to determine who will be prime minister and lead the National Assembly.

The snap elections were a huge gamble for Mr Macron.

It does not appear to have paid off as he now faces the prospect of leading the country alongside a prime minister opposed to most of his domestic policies.

The centre-left coalition coalition calls itself the New Popular Front (NPF), named after a similar alliance formed in the 1930s against the rise of fascism in France. 

It includes environmentalist parties, the French Socialists and Communists and the hard-left France Unbowed party.

Prime Minister Gabriel Attal on Sunday announced he would hand his resignation on Monday morning local time, adding he will carry out his duties as long as required.

Mr Attal said early polling results heralded a "new era for our nation" in the face of an unprecedented political situation. 

"Tonight, the political group I represented in this campaign, even if it scored three times more than what was predicted in recent weeks, does not have a majority. And so, being loyal to republican tradition and to my principles, I will hand in my resignation letter to the president," he told reporters.

"From tomorrow, the centre of gravity of power will be, through French people's desire, more than ever in the hands of the parliament, in the hands of the representatives of the nation, and so in the hands of our fellow citizens.

"A new era also starts for the values that our candidates represented … from tomorrow, our political space should get to work to build a new political offer, to think always and above all of the French, of their lives, and to personify hope for them once again."

NPF won the most seats in the second voting round of parliamentary elections. Its victory marks a huge setback for the far right, and will leave parliament divided in three big groups with hugely different platforms and no tradition at all of working together.

Leftist leader Jean-Luc Mélencho said the surprise results of the legislative elections were an "immense relief for a majority of people in our country".

But a hung parliament with no single bloc coming close to getting the 289 seats needed for an absolute majority in the National Assembly would be unknown territory for modern France.

The projections, if confirmed by official counts, will spell intense uncertainty for a pillar of the European Union and its second-largest economy, with no clarity about who might partner with Mr Macron as prime minister in governing France.

Unlike other countries in Europe that are more accustomed to coalition governments, France does not have a tradition of representatives from rival political camps coming together to form a working majority.

France has a two-house system of government in which the president and the parliament share power. The president is elected by popular vote and appoints the prime minister, as well as the cabinet ministers.

The government must secure the support of the majority of MPs in the National Assembly to stay in power.

Mr Macron had been facing difficulties passing legislation within the the National Assembly, after failing to secure an absolute majority in June 2022.

In the country's European Parliament vote on June 6-9, the far-right RN gained more than 30 per cent of the vote or about twice as much as Mr Macron's party.

The far-right party led by Marine Le Pen received 33 per cent of the popular vote in the first round of parliamentary elections last weekend — a result that put France the closest it had been to having a far-right government since World War II.

Jordan Bardella, president of the French far-right National Rally party.(Reuters: Sarah Meyssonnier)

But the second round of the election for the 577-seat National Assembly looks to place RN in third spot. 

In a sombre speech after the vote, Jordan Bardella, president of the National Rally and the man who would have become prime minister had the far right won a majority, denounced the political manoeuvring ahead of the vote that led the party to fall far short of expectations. 

He blamed Mr Macron for "pushing France into uncertainty and instability".

An unprecedented number of candidates who qualified for the run-off stepped aside to allow an opponent to go head-to-head with the National Rally candidate, increasing the chances of defeating them.

"I say tonight, with gravity, that depriving millions of French people of the possibility of seeing their ideas brought to power will never be a viable destiny for France," Mr Bardella said. 

"Tonight, by deliberately taking the responsibility to paralyse our institutions, Emmanuel Macron … is consequently depriving the French people of any responses to their daily problems for many months to come.

"In the midst of a purchasing power crisis, with insecurity and disorder hitting the country hard, France is deprived of a majority, of a government to act, and therefore of a clear course to turn France around."

Posters on a French street read "The far right feeds on despair" and "Barrier against the far right".(Reuters: Violeta Santos Moura)

When he called the snap parliamentary elections, Mr Macron said the rise of nationalists was dangerous for France and for Europe.

"I can't pretend nothing happened," he said in an address to the nation from the Élysée presidential palace.

"I've decided to give you back the choice of our parliamentary future through the vote. I am therefore dissolving the National Assembly."

Tensions were running high on Friday as France's election campaign came to an end with more than 50 candidates and activists physically assaulted during the shortest election campaign in modern French history.

The snap elections in this nuclear-armed nation have a potential impact on the war in Ukraine, global diplomacy and Europe's economic stability. 

They're almost certain to undercut Mr Macron for the remaining three years of his presidency.

ABC/wires