Macron, who was re-elected president in April against far-right Marine Le Pen, needs a majority in his lower house in parliament to be free to push for tax cuts and changes to the welfare system. But a historic alliance of parties on the left, led by Jean-Luc Mélenchon’s hard-line France Unbowed party with the Socialists and Greens, is seeking to massively increase its seats and lower Macron’s center-back ratings. Polls show that, in terms of voting intentions, Macron’s central alliance, the Ensemble (Together), is inextricably linked to the Mélenchon coalition, known as the Nupes, or the New People’s Ecological and Social Union. However, the voting system for the parliament based on the French constituency, in the first place, means that the exact number of seats for each group remains difficult to predict. Much will depend on the turnout – which could be below 50% and reach a record low. Polls suggest Macron’s center-right coalition will win the largest share of the 577-seat parliament – with between 260 and 320 seats. But that suggests there is a possibility Macron’s centers may not have an absolute majority, which requires 289 seats. If Macron’s party and its central allies fail to secure a majority, it would be a setback for the president and could lead to messy bill deals with right-wing parties in parliament or an unwanted cabinet reshuffle. The challenge from the recently united left was greater than expected, as support for Mélenchon’s alliance is steadily rising in opinion polls. The alliance could take between 155 and 205 seats and become the main opposition force in parliament, according to opinion polls. Macron and the ministers stepped up their campaign this week, warning that Melanson was a dangerous and extremist who would kill the European Union, “ally with Russia” and add to the “global disorder”. Lepen’s far-right National Rally party, which won eight seats in 2017, hopes to win at least 15 seats this time around, allowing it to form a parliamentary group and gain more visibility in the National Assembly. The poll shows that the party could win between 20 and 65 seats. Although Le Pen came second in the presidential election with a record high of 41%, the voting system for parliament has proved to be historically difficult for her party in the parliamentary elections. Polls opened in mainland France at 8 a.m. (7 a.m. BST) after overseas voters cast their ballots earlier in the weekend. The polls close at 8 pm. Of the 577 members of the National Assembly, eight represent France’s overseas territories and 11 represent French nationals living abroad. Sunday’s first round of voting will decide which candidates will face each other in each constituency for the last week of the campaign. The shape of the new parliament will become clear only after the second round on 19 June.