President Emmanuel Macron on Monday was to start efforts to extract France from its most severe political uncertainty in decades after the left defeated the far right in elections with no group winning an absolute majority.
The outcome of the legislative elections, called by Macron three years ahead of schedule in a bid to reshape the political landscape, leaves France without any clear path to forming a new government three weeks before the Paris Olympics.
Prime Minister Gabriel Attal is due to submit his resignation to Macron on Monday but has also made clear he is ready to stay on in a caretaker capacity as weeks of political uncertainty loom.
The left is emerging as the biggest group in the new parliament but has yet to even agree on a figure who it would want to be the new prime minister.
The unprecedented situation is taking shape just as Macron is due to be out of the country for most of the week, taking part in the NATO summit in Washington.
"Is this the biggest crisis of the Fifth Republic?" that began in 1958, asked Gael Sliman, president of the Odoxa polling group.
"Emmanuel Macron wanted clarification with the dissolution, now we are in total uncertainty. A very thick fog."
After winning the June 30 first round by a clear margin, the results were a major disappointment for the far-right National Rally (RN) of Marine Le Pen, even if her forces are set to boast about their biggest ever contingent in parliament.
Macron's centrist alliance will have dozens fewer members of parliament, but held up better than expected and could even end in second.
The left-wing New Popular Front (NFP) -- formed last month after Macron called snap elections -- brought the previously deeply divided Socialists, Greens, Communists and the hard-left France Unbowed (LFI) together in one camp.
Projections by major polling agencies showed the NFP set to be the largest bloc in the new National Assembly with 177 to 198 seats, Macron's alliance on 152 to 169 seats and the RN on 135 to 145 seats.
That would put no group near the 289 seats needed for an absolute majority and it remains unclear how a new government could be formed.
Macron, who has yet to speak in public about the projections, is calling for "prudence and analysis of the results", said an aide, asking not to be named.
LFI lawmaker Clementine Autain called on the NFP alliance to gather on Monday to decide on a suitable candidate for prime minister.
In key individual battles, Le Pen's sister Marie-Caroline narrowly lost out on being a lawmaker, but former president Francois Hollande will return to frontline politics as a Socialist member of parliament.
Firebrand leftist Jean-Luc Melenchon, leader of LFI and the controversial figurehead of the NFP coalition, demanded that the left be allowed to form a government.
Only one week ago, some polls had indicated the RN could win an absolute majority with Le Pen's 28-year-old lieutenant Jordan Bardella becoming prime minister.
Instead, he expressed fury.
Bardella dubbed the local electoral pacts that saw the left and centrists avoid splitting the anti-RN vote as an "alliance of dishonour".
He said it had thrown "France into the arms of Jean-Luc Melenchon's extreme left".
Le Pen, who wants to launch a fourth bid for the presidency in 2027, declared: "The tide is rising. It did not rise high enough this time, but it continues to rise and, consequently, our victory has only been delayed."
The first round saw more than 200 tactical-voting pacts between centre and left-wing candidates in seats to attempt to prevent the RN winning an absolute majority.
This has been hailed as a return of the anti-far right "Republican Front" first summoned when Le Pen's father Jean-Marie faced Jacques Chirac in the run-off of 2002 presidential elections.
The question for France now is if this alliance of last resort can support a stable government, dogged by a still substantial RN bloc in parliament led by Le Pen herself as she prepares a 2027 presidential bid.
"It may take many weeks to resolve the muddle while the present government manages current business."
