An alliance of France’s leftwing and Green parties led by the hard-left Jean-Luc Mélenchon has rejected calls to form a single parliamentary bloc less than 24 hours after it won the second largest number of seats in legislative elections. The split came as the French president, Emmanuel Macron, held talks with members of his centre-right party over how to form a government after it unexpectedly lost its absolute majority in Sunday’s second-round vote. It emerged on Monday evening that Macron has invited opposition party leaders including Mélenchon and Marine Le Pen for talks at the Élysée Palace. “Since there is no majority, the question of how to carry out the necessary reforms for the country is posed,” a presidential source told French journalists. “That is why there will be meetings with the political groups.” The aim of the meetings was “dialogue and exchange for the greater good of the nation” and to find solutions to the political stalemate created by Macron losing his absolute majority in parliament. “As the guarantor of the institutions of state, the president of the republic is determined to act in the interest of the French people, as the custodian of the mandate they have given him,” the source added. It was unclear whether the reported disintegration of La Nouvelle Union Popular, Ecologique et Sociale (Nupes – the New Popular Ecological and Social Union) would help or hinder the president, who now faces having to negotiate alliances and compromises to push through any legislation during his second term in office. Mélenchon had called in comments to the press on Monday for the parties in the hastily arranged Nupes to form a single parliamentary opposition group in the Assemblée Nationale, the lower house, but his suggestion was rejected outright by the three main parties – Socialists, Greens/Ecologists and Communists – who had joined forces with his radical left La France Insoumise (LFI) to fight the general election. He described the result of the election as a “disappointment” for Nupes and said it had created an “unmanageable situation” in the country. “We are and we must remain a united alternative, in other words Nupes should form a single group in parliament so it is clear and there can be no possible discussions about who is running the opposition in the country,” he said. Political analysts suggested Mélenchon had made a tactical error by not trying to convince his allies to join forces before he suggested it to the media. Gabrielle Siry-Houari, spokesperson for the Socialist party (PS), said there had been no agreement to form a single group in parliament after the election and declared: “It makes no sense politically.” “This was not the spirit of the coalition we formed. If we want to represent the opposition we have to know how to listen and be aware of the different opinions of those in the coalition,” she told BFMTV. Another PS spokesperson, Pierre Jouvet, said: “There was never any question of forming a single group. There will be a Socialist group in the Assemblée Nationale.” Alain Coulombel, of Europe, Ecologie, Les Verts (EELV) said the suggestion was “out of the question”, as did a spokesperson for the Communist party leader, Fabien Roussel. Antoine Léaument, from LFI, who was elected to parliament as part of the Nupes alliance, said it was important to unite to dispel the idea that Le Pen’s far-right Rassemblement National (RN), which made unprecedented gains in the election, was now the main opposition. He denied Mélenchon had overplayed his hand by speaking to the press about forming a single parliamentary group before calling his partners. “He made a public proposal out of respect for our allies but also for our voters,” Léaument said. Just two months after re-electing him for a second term at the Elysée, French voters have left Macron’s centrist alliance Ensemble! flanked by the hard left and far right. His programme is stopped in its tracks unless he can forge new alliances on the centre-right or centre-left. France’s traditional parties of the left and right have weakened since Macron and his centrist La République En Marche, since renamed Renaissance, came to power in 2017, while the far right and radical left have strengthened. The gains by both meant that Macron’s group won 245 seats in the second round vote on Sunday, far short of the 289 needed for an absolute majority. Nupes won 131 seats, while the far-right RN won 89 seats, an unprecedented surge in popularity. The traditional right Les Républicains (LR), who had joined forces with the Union des Démocrates et Indépendants (UDI), took just 62 seats. Christian Jacob, president of LR, ruled out any deal with Macron or his party. “We are in opposition to the government of Emmanuel Macron. There is no question of a pact, coalition or any kind of agreement. But we will be a respectful opposition on the individual laws proposed,” he said. “[Macron] has split the country and played on the extremes and left France in the situation it is today. We have kept our independence. It may have cost us dearly but we can at least look ourself in the mirror.” Jacob described Nupes as a “communication trick” but the former journalist and television presenter Aymeric Caron, elected to parliament on the Nupes ticket, said he believed keeping the leftwing coalition together after its electoral success was “still doable”. The future of the French prime minister, Élisabeth Borne, who was appointed a month ago, is now in question given Macron’s weakened standing in the parliament. Macron had insisted before the election that all ministers who lost their seats would have to stand down. Borne, who escaped being forced to give up her post definitively by narrowly winning her Normandy constituency, said on Sunday night: “The situation is a risk for our country, given the challenges we have to face at the national and international level. We have to draw the consequences of this vote.” Three newly appointed ministers lost their seats and will have to stand down: Brigitte Bourguignon, the health minister; Amélie de Montchalin, theenvironment minister; and Justine Benin, secretary of state for the sea.