French election exit polls show strong result for Marine Le Pen and ...

Marine Le Pen's far-right National Rally party has secured the first round of France's parliamentary elections, with 34 per cent of voters, exit polls show. 

France's high-stakes legislative elections propelled the National Rally to a strong lead in the first-round vote on Sunday, dealing another slap to President Emmanuel Macron.

The New Popular Front – a newly created far-left coalition – has taken 28.1 per cent and Emmanuel Macron's centrist Renaissance party has taken 20.3 per cent.

Candidates who win more than 12.5 per cent of the vote will go through to the second round of voting on July 7 – which will determine the final make-up of France's next National Assembly.

The projections indicated that Mr Macron's decision to call voters back to the polls for the second time in three weeks appeared to have backfired.

Marine Le Pen and Jordan Bardella have positioned the Rassemblement National party as a major opposition force in France.(ABC News: Riley Stuart)

He called the snap poll after his party lost out to Ms Le Pen's National Rally in the European Parliamentary elections last month. 

French polling agencies said Mr Macron's grouping of centrist parties could finish a distant third in the first-round ballot. 

Those projections put Macron's camp behind both Ms Le Pen and a new left-wing coalition of parties that joined forces to keep her anti-immigration party with historical links to anti-Semitism from being able to form the first far-right government in France since World War II.

But with another torrid week of campaigning to come before the decisive final voting next Sunday, the election's ultimate outcome remained uncertain.

Ms Le Pen said Mr Macron's camp has been "almost wiped out" during the first round. 

Addressing a jubilant crowd waving French tricolor flags of blue, white and red, Ms Le Pen called on her supporters and voters that didn't back her party in the first round to push it over the line and give it a commanding legislative majority.

In that scenario, Ms Le Pen's 28-year-old protege, Jordan Bardella, would become prime minister.

Mr Macron, who has said he will not step down before his term expires in 2027, would be forced into an awkward power-sharing arrangement called "cohabitation" in France.

Mr Bardella called on voters to choose his party over a "dangerous far left". 

"The choice is clear," Mr Bardella said, accusing the left-wing coalition of campaigning for "disarming the police" and "opening wide the doors for immigration".

He also criticised leftist leaders for "insulting institutions and anyone who thinks differently from them".

"The time has come to put leaders at the head of the country who understand you," he said.

Gabriel Attal, 35, is France's youngest prime minister. (Reuters: Charles Platiau )

In a written statement to the press, Mr Macron called on voters to rally behind candidates who are "clearly republican and democratic", which, based on his recent declarations, would exclude candidates from the RN and from the hard-left France Unbowed (LFI) party.

His former prime minister, Edouard Philippe, explicitly called on the candidates from his party to drop out if they were in third position and rally behind candidates excluding the RN and LFI.

On the left, the Socialist and LFI leaders also called on their third-placed candidates to drop out to block the RN.

LFI leader Jean-Luc Melenchon said the second-placed NFP alliance would withdraw all its candidates who came third in the first round.

"Our guideline is simple and clear: not a single more vote for the National Rally," he said.

Mr Macron and Prime Minister Gabriel Attal urged voters to rally against the far-right in the second round.

"Not a single vote must go to the National Rally," Mr Attal said.

"France does not deserve that."

Mr Bardella said he was ready to be prime minister — if his party wins an absolute majority. 

He has ruled out trying to form a minority government and neither Mr Macron nor the NFP will form an alliance with him.

"I will be a 'cohabitation' prime minister, respectful of the constitution and of the office of President of the Republic, but uncompromising about the policies we will implement," he said.

Elections for the 577 seats in France's National Assembly are a two-round process.

In constituencies where no candidate won outright in the first round, the top two candidates, as well as any candidate with more than 12.5 per cent of the total number of registered voters in that constituency, move to a second round.

Whoever gets the most votes in the second round wins the seat.

The high turnout on Sunday means some 300 constituencies are now facing potential three-way run-offs which, in theory, favour the RN.

To prevent these three-way run-offs and block the RN, France's centre-right and centre-left politicians have long practised what they call a "republican front", whereby the third-placed candidate drops out of the race and urges voters to rally behind the second-placed candidate.

All candidates through to the run-off have until Tuesday evening to decide whether to stand down or run the second round.

Jordan Bardella is 28 years old. (Reuters: Christian Hartmann)

But the effectiveness of the "republican front" has weakened over the years, and many voters no longer heed the advice of party leaders.

It is also possible that candidates will refuse to drop out despite guidance from political HQs in Paris.

But talks over the next 48 hours will be crucial and could swing the results significantly, potentially deciding whether the RN reaches an outright majority in parliament or not.

That makes the result of the second round extraordinarily hard to predict. Even pollsters have urged caution on their own seat projections.

ABC/wires