After trying to hold up the march a group of protesters ran amok along the route, destroying a McDonald's restaurant near Austerlitz station, east of the city centre, and setting it ablaze. They also torched vehicles at a car dealership, along with a mechanical digger and a scooter, leaving a trail of destruction and plumes of dark smoke billowing into the air. The worst unrest in months in Paris comes at a time of heightened tensions over Macron's reform of the public sector and follows a showdown between police and anti-capitalist squatters at a sprawling commune in western France. Macron condemned the violence, posting on Twitter during his trip to Australia: "Everything will be done so that the perpetrators are identified and held responsible for their actions." He added the demonstrations would be treated with "absolute firmness". 'Macron makes us mad' The police had warned of the risk of extremist groups using May Day to set up a rematch of the clashes seen during demonstrations last year over Macron's labour reforms and at an anti-capitalist camp in western France that was demolished by police earlier this month. The scenes of looting and destruction overshadowed the May Day march, which drew between 20,000 and 55,000 peaceful protesters according to police and union estimates. Polls show the French supporting those reforms but being more critical of Macron's fiscal policy, seen as favouring the wealthy over the working and middle classes. "Macron is the president of the rich," Genevieve Durand, a retired public servant who took part in a march in the central city of Clermont-Ferrand, told AFP, echoing a label that has clung to the centrist leader. The energetic 40-year-old, who vowed during campaigning to make France more competitive, has insisted he will not budge from his course. "I'm doing what I said I would," he said during a recent television interview to mark the first anniversary of his election on May 7.