Protesters have attacked a police station and smashed bank windows during anti-labour reform rallies in France, while the hardline CGT union has sought to choke off fuel supplies in a showdown with a government that said it would not back down.
Sixteen people were arrested in Paris where 18,000-19,000 marched on Thursday (local time) according to police, far fewer than in the first protests against the labour law over the past three months.
In the southwestern city of Bordeaux, about 100 people targeted a police station, throwing objects and damaging a police car.
In Paris and in the western city of Nantes, bank windows were broken and protesters clashed with police, who responded with tear gas.
The next big day of protests is planned on June 14, four days after the Euro 2016 soccer tournament opens in France.
The CGT warned it could be disrupted if the government refuses to withdraw the draft reform bill.
"The government has the time to say 'let's stop the clock' and everything will be ok," CGT chief Philippe Martinez said when asked by Reuters if his union was willing to disrupt the soccer contest. The union wants the bill scrapped.
"We will disrupt the Euro (tournament) and the government will be the one to blame," 33-year-old sales worker and CGT representative Naima said during the protest march.
As turnout at protests has dwindled, the CGT has turned to sectoral strikes, with workers stopping work at oil refineries, nuclear power plants and the railways, as well as erecting road blocks and burning wooden pallets and tyres at key ports like Le Havre and near distribution hubs.
Prime Minister Manuel Valls said the government would not withdraw the law and would break up refinery blockades, saying there could be some tweaks to the reforms but not on any of its key planks. He was backed by the country's other big trade union, the CFDT.
"There is no question of changing tack, even if adjustments are always possible," said Valls, who rejected calls to scrap the part of the law that put the CGT on the warpath.
That section would let companies opt out of national obligations on labour protection if they adopt in-house deals on pay and conditions with the consent of a majority of employees.
The government pushed the bill through the lower house of parliament with a decree as it struggled to find enough lawmakers to back it. The final vote is expected in July.
Laurent Berger, head of the bigger CFDT union and a backer of the reform, said: "The political and industrial relations climate has turned hysterical ... let's calm things down."