The French government has used controversial special constitutional powers to force through a rise in the pension age amid chaotic scenes in parliament in which radical left MPs sang La Marseillaise at the top of their voices to stop the prime minister, Élisabeth Borne, from speaking. The president, Emmanuel Macron, took a last-minute decision to avoid a parliamentary vote and instead push through his unpopular plan to raise the pension age from 62 to 64. Minutes before MPs in the lower house were to vote, Macron was still holding a series of frantic meetings with senior political figures, and suddenly chose to use special powers instead of risking a vote, which he appeared poised to lose. He opted to invoke article 49.3 of the constitution, which gives the government power to bypass parliament. MPs on the left shouted “Resign! Resign!” at Borne, and members of the radical left party France Unbowed sang the national anthem so loudly that Borne could at first not speak and the session had to be suspended before she tried again to be heard. Borne told parliament the bill would be pushed through because the government could not “gamble the future of our pensions”. Macron had told cabinet ministers that “the financial risks were too great” if the law had been rejected by MPs, according to reports from inside talks at the Élysée. Shortly afterwards, hundreds of people gathered in a spontaneous protest at Place de la Concorde in the centre of the city, as trade unions promised to intensify the strikes and street demonstrations that have taken place since January. The head of the hardline CGT union, Philippe Martinez, said forcing through the law “shows contempt towards the people”. Police fired teargas and charged in an effort to disperse the crowd on Thursday night, as some protesters threw cobblestones. In several other French cities including Marseille there were also spontaneous protests against the reform. Police have arrested 120 people in Paris, according to Le Figaro. A police officer was reportedly injured in one standoff with protestors and rioters. French unions called for another day of strikes and action against the reform on Thursday 23 March. Politicians on the left called the government’s move a major defeat and a sign of weakness. The government was accused of being brutal and undemocratic. Borne had seemed aware in recent weeks of the uproar and protests that could be prompted by the use of “49.3” special powers, and had appeared reluctant to use them. Opposition politicians will call for a vote of no confidence in the government in the next 24 hours. Whether this can pass will depend on whether polarised opposition parties would group together. Any no-confidence vote would need the support of the right’s Les Républicains to pass, but the party’s leader, Éric Ciotti, said it would not support such a vote. The political crisis over pensions changes highlights how Macron’s position has been severely undermined in the national assembly after his centrist grouping failed to win an absolute majority in parliamentary elections last June. Without one, it had relied on winning over MPs from the Les Républicains party to support the pensions project, but then decided the numbers were not enough. The Communist MP Fabien Roussel called on street protesters and trade unionists to keep mobilising. Under Macron’s pension changes, the minimum general retirement age will increase from 62 to 64, some public sector workers will lose privileges and there will be an accelerated increase in the number of years of work required to qualify for a full pension. Some politicians from the centrist Modem party, which is allied with Macron’s Renaissance group in parliament, said forcing the bill through was a mistake. Erwan Balanant, a Brittany MoDem MP, said he had left the parliament chamber “in a state of shock”. Other centrist MPs said it was a waste and showed weakness. “It’s a total failure for the government,” the far-right leader Marine Le Pen told reporters afterwards, adding that Borne should resign. Polls show that two-thirds of French people oppose the pension changes. Transport workers, energy workers, dockers, teachers and public sector workers, including museum staff, have held strikes in recent weeks. A continuing rubbish-collection strike and has led to more than 7,000 tonnes of waste building up across half of Paris. Trade unions say the reform will penalise low-income people in manual jobs who tend to start their careers early, forcing them to work longer than graduates, who are less affected by the changes. The government has argued that raising the retirement age, scrapping privileges for some public sector workers and toughening criteria for a full pension are needed to prevent big deficits building up. The change would bring France into line with its European neighbours, most of which have raised the retirement age to 65 or older.