Emmanuel Macron’s centrist grouping was neck and neck with a new leftwing alliance led by the hard-left Jean-Luc Mélenchon in the vote share of the first round of parliamentary elections, according to early projections. A frantic final week of campaigning will begin on Monday before the second round, as Macron’s centrists still hope to edge ahead but face uncertainty over whether they can win a crucial majority of seats in parliament. A historic alliance of parties on the left, led by Mélenchon’s France Unbowed party and including the Socialists and the Greens, was slightly ahead on 25.6% – a strong showing which presents a challenge to Macron. The president’s centrist alliance, Ensemble (Together), was projected to take 25.2% of the vote, according to estimations by Ipsos-Sopra Steria for France Télévisions. Turnout on Sunday was estimated to have hit a record low of about 47%, according to polling firm projections, after candidates described the mood among voters as angry and disillusioned at the political class. Olivia Grégoire, the government spokesperson, said the low turnout was the “key issue”. Macron, who was re-elected president in April against the far-right’s Marine Le Pen, needs a majority for his centrist grouping in the national assembly in order to have a free hand for his proposals to cut taxes and make changes to the welfare system. The parliamentary results will set the balance of power for Macron’s second term, defining his capacity to deliver domestic policies such as raising the retirement age and overhauling the benefits system. Mélenchon’s alliance – known as the Nupes, or the New Popular Ecological and Social Union – is seeking to increase its seats and reduce the number of Macron’s centrists. The coalition’s platform includes a significant minimum wage increase, lowering the retirement age to 60 and a freeze in basic food and energy prices to address the cost of living crisis. France’s constituency-based, first-past-the-post voting system for parliament means that the exact number of seats for each grouping remains hard to predict. The shape of the new parliament will become clear only after the second round on 19 June. Based on early estimations, Ispos predicted Macron’s centrist alliance would win the greatest share of the 577-seat parliament – taking between 255 and 295 seats. This suggested there was a chance they could fall short of an absolute majority, which requires 289 seats. If Macron’s party and his allies fail to secure a majority, it would be a setback for the president and could prompt messy bill-by-bill deals with rightwing parties in parliament or an unwanted cabinet reshuffle. The left alliance could take between 150 and 190 seats, according to Ipsos. Macron and ministers had stepped up campaigning this week, warning Mélenchon was dangerous and an extremist who would kill the European Union, “ally with Russia” and add to “world disorder”. Le Pen’s far-right National Rally party, which won eight seats in 2017, hopes this time to get at least 15 seats, allowing it to form a parliamentary group and gain greater visibility at the national assembly. Ipsos suggested the party could take up to 45 seats. Despite Le Pen coming second in the presidential election with a historic high of 41%, the first-past-the-post voting system for parliament has historically proved difficult for her party in legislative elections. Le Pen, from the stronghold of Hénin-Beaumont, in northern France, called on her voters to turn out for her party against what she called Macron’s “brutal” style of politics. She said France was suffering, citing the cost of living crisis as well as the treatment of English fans at the Champions League final in Paris, seen as damaging France’s image abroad. Le Pen’s new rival on the far right, the former TV pundit Éric Zemmour, was eliminated in the first round after standing in a constituency around Saint-Tropez in southern France. The first weeks of the new government have been tense in the run-up to the parliamentary elections, with hospital strikes and concerns about the cost of living, and Macron has been accused by Ukraine of being too accommodating to Russia. Macron’s new disabilities minister, Damien Abad, has faced two rape accusations – which he has denied – but which prompted street demonstrations over women’s rights, while the new prime minister, Élisabeth Borne, has yet to make an impact. Borne, who is running for the first time in a Normandy seat, was well-placed for the second round run-off. Jean-Michel Blanquer, Macron’s former education minister, was eliminated in the first round in the Loiret. Macron has made it clear that serving ministers who are running for election will have to step down if they lose.