Leading left-wing French politician Raphael Glucksmann on Friday threw his weight behind a new coalition of the left in the run-up to historic elections, while far-right powerhouse Marine Le Pen pledged a "national unity government" if her party wins the snap polls.
President Emmanuel Macron on Sunday stunned France by calling snap legislative elections for June 30, with a second round on July 7, after Le Pen's far-right National Rally scored more than double the number of votes of his centrist alliance in last week's European elections.
After four days of intense negotiations, left-wing leaders including the hard-left France Unbowed (LFI), the Socialist, Communist and Green parties said they had agreed -- despite long-running policy differences -- on an election alliance called the New Popular Front.
"We can't leave France to the Le Pen family," 44-year-old Glucksman, who led the Socialist-backed list in the European elections, told broadcaster France Inter.
Glucksmann backed the new coalition, saying it was the "only way" to prevent a far-right victory in the forthcoming polls.
The name of the alliance is a nod to the Popular Front, a political alliance founded in France in 1936 to combat fascism.
Le Pen took over as the leading figure of the nationalist, populist National Front from her father Jean-Marie Le Pen, renaming it and standing three times as its presidential candidate.
Opinion polls suggest her party will massively increase its parliamentary presence from its current 88 out of 577 seats.
Glucksmann accused Macron of plunging France "into chaos".
"He has opened the way to power for the far right. Since Sunday night, I've had a knot in my stomach," he said.
The co-founder of Place Publique, a progressive left movement, waged a dynamic campaign for the European elections and gained around 14 percent, coming hot on the heels of Macron's camp.
The parties in the new left-wing alliance were due to unveil their programme at a news conference on Friday.
It remained unclear who would lead the New Popular Front and be their candidate for prime minister.
Glucksmann ruled out the LFI's abrasive leader Jean-Luc Melenchon, saying: "We need someone who can achieve consensus."
Francois Hollande, the Socialist former president, also pronounced himself in favour of the new union, telling broadcaster TF1 on Thursday evening the left forces had "got beyond our differences".
Hitting the campaign trail in Pas-de-Calais in northern France, Le Pen claimed National Rally could win the elections and form a "national unity government".
"We need to pull France out of the rut," said the 55-year-old, who is widely expected to run for a fourth time in the 2027 presidential election.
"We will gather all French people -- men and women of goodwill -- who are aware of the catastrophic situation in our country," she said, adding it would be up to 28-year-old RN party leader Jordan Bardella to "choose his team".
By contrast, France's right-wing parties were mired in infighting.
Eric Ciotti, leader of the mainstream conservative Republicans (LR), broke a historic taboo this week, announcing that his party would form an electoral alliance with the far-right RN.
The rest of the party leadership promptly expelled him.
Ciotti insists he remains party chairman and is challenging his ousting. A Paris court was set to examine the case on Friday.
For its part, the Republicans' political bureau held a fresh meeting by videoconference on Friday and confirmed Ciotti's expulsion, party sources told AFP.
Bardella, speaking on television, said the RN and the Republicans would put up joint candidates in 70 of France's 577 parliamentary constituencies, hailing what he said was a "historic agreement."
He said he wanted to obtain the "broadest possible majority".
Macron remained defiant, defending his decision to dissolve parliament and call snap elections.
Speaking at a G7 summit in Italy on Thursday, he said his G7 counterparts praised his move.
"They all said: 'This is courageous'", Macron told journalists.
He indicated he hoped to score points by hosting the Olympic Games in Paris from July 26, saying French people would want leaders "who have prepared for these Games".
