In a historic first since World War II, the French far-right bloc – led by the National Rally (RN) party – won the first round of the country's parliamentary elections with around 33% of the votes, according to the Interior Ministry.

They were followed by the leftwing New Popular Front with 28% while President Emmanuel Macron's centrist bloc reached 20%, the ministry said.

Marine Le Pen's RN party scored historic gains in the election held Sunday, in a huge setback for President Emmanuel Macron who had called the snap election after his ticket was trounced by the RN in European Parliament elections earlier this month.

The RN's share of the vote was comfortably ahead of leftist and centrist rivals, including Macron's Together alliance, a hastily assembled left-wing coalition.

The results were in line with exit polls and opinion surveys ahead of the election and were met with jubilation by Le Pen's supporters.

However, they provided little clarity on whether the anti-immigrant, eurosceptic RN will be able to form a government to "cohabit" with the pro-EU Macron after next Sunday's run-off.

A longtime pariah for many in France, the RN is now closer to power than it has ever been. Le Pen has sought to clean up the image of a party known for racism and anti-semitism, a tactic that has worked amid voter anger at Macron, the high cost of living and growing concerns over immigration.

At Le Pen's Henin-Beaumont constituency in northern France, supporters waved French flags and sang the Marseillaise.

"The French have shown their willingness to turn the page on a contemptuous and corrosive power," Le Pen told the cheering crowd.

The RN's chances of winning power next week will depend on the political dealmaking made by its rivals over the coming days.

In the past, center-right and center-left parties have teamed up to keep the RN from power, but that dynamic, known as the "republican front," is less certain than ever.

The High turnout on Sunday suggests France is heading for a record number of three-way run-offs. These generally benefit the RN much more than two-way contests, experts say.

The horsetrading began almost immediately on Sunday night.

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.

Political leaders from the center-left and far-left all called on their third-placed candidates to drop out.

"Our guideline is simple and clear: not a single more vote for the National Rally," France Unbowed leader Jean-Luc Melenchon said.

However, the center-right Republicans party, which split ahead of the vote with a small number of its lawmakers joining the RN, gave no guidance.

Possible prime minister

Jordan Bardella, the 28-year-old RN party president, 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 Macron nor the NFP leftist group 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.

The mood was gloomy at the Republique square in Paris, where a few thousand anti-RN protesters gathered at a rally of the leftist alliance Sunday night.

Najiya Khaldi, a 33-year-old teacher, said she felt "disgust, sadness and fear" at the RN's strong results.

"I am not used to demonstrating," she said. "I think I came to reassure myself, to not feel alone."