To further complicate things, leaders within each camp disagreed on who to reach out to in order to try to cobble together a deal. Internal tensions within parties also grew as members jostled for influence in rebuilding a political landscape blown apart by the snap ballot.
And any government - of the left, centre, or a broader coalition - could quickly fall victim to a confidence vote from the opposition if it has not secured sufficient solid support.
"Today, we find ourselves in a quagmire since no one is able to know from what rank the prime minister will come, or what policy will be pursued for the country," far-right leader Marine Le Pen told reporters as she arrived in parliament.
Le Pen condemned pre-election deals she said kept her National Rally (RN) party from power.
"To say the least, this is not a great success for Emmanuel Macron," Le Pen quipped.
ALTERNATIVES
It would be customary for Macron to call on the biggest parliamentary group to form a government, but nothing in the constitution obliges him to do so.
Options include a broad coalition and a minority government, which would pass laws in parliament on a case by case basis, with ad hoc agreements.
Phones are ringing constantly, political sources have told Reuters, with some centrists now hoping they can reach a deal with the conservative The Republicans and edge the left out.
"I think there is an alternative to the New Popular Front," Aurore Berge, a senior lawmaker from Macron's Renaissance group told France 2 TV. "I think the French don't want the NFP's platform to be implemented, I think they don't want tax increases."
"We are the only ones who can extend (our base)," she said.
Meanwhile, leftist leaders also took to the airwaves to stress that, having topped the election, they should run the government. But without a deal yet on who could be prime minister, they now face growing competition from the right and centre.
Carole Delga, from the Socialist Party, stressed that the left on its own cannot govern, and must extend its hand to others - but on the basis of the NFP's tax-and-spend programme.
But others took a harder line.
"The NFP has the greatest number of deputies in the National Assembly, it is therefore up to the NFP to constitute a government ... this is what we are working towards," Manuel Bompard, from France Unbowed, told LCI TV.
