Hundreds of thousands of workers have taken part in strike action across France on Thursday, after trade unions called for a day of protests against budget cuts.
Organisers said one million people turned out, while the interior ministry estimated the number at 500,000, with 80,000 police officers deployed.
Scuffles were reported in the cities of Lyon and Nantes, and in Paris small-scale clashes broke out between police and protesters.
Officers in riot gear used tear gas and shields to disperse crowds in the centre of the capital after some protesters damaged a small number of businesses and buildings.
The strikes come barely a week after Sébastien Lecornu, a close ally of President Emmanuel Macron, was appointed prime minister following the toppling of François Bayrou's government.
Public transport was heavily disrupted on Thursday, with many metro lines in Paris reported shut, while protesters blocked roads and streets in major cities across France. Students gathered in front of schools and universities in the capital and beyond, blocking entrances and chanting slogans. Around a third of teachers walked out.
Pharmacists also adhered to the strike, with 98% of pharmacies expected to stay closed.
More than 300 people were detained across France, the interior ministry said.
Unions have called for more spending on public services, higher taxes on the wealthy and for the budget cuts outlined by the short-lived Bayrou government to be axed.
Cyrielle, a 36-year-old IT worker, told the BBC she was striking because Macron's economic and social policies don't suit me, nor did Bayrou's budget. She was participating in a tightly-policed, large demonstration in central Paris.
I would like more resources invested in public services and culture. Perhaps a percentage of people with enormous wealth could contribute a little more, she said, adding that if the new government leaned more to the left, that would be the beginning of a solution.
Sophie Binet, the leader of one of France's major trade union groups, the General Confederation of Labour (CGT), stated: We need to be out in force, that's how we gather strength to keep fighting... to force the government and the employers to put an end to policies that only serve the richest.
Bruno Retailleau, the outgoing interior minister, warned, We will be uncompromising and relentless, emphasizing police instructions to make arrests at the slightest provocations.
Jean-Luc Mélenchon, leader of the radical left party France Unbowed (LFI), urged strikers to be disciplined, warning that violent actions would benefit the government.
The protests follow a previous event where around 200,000 participated in demonstrations against proposed budgets, which aimed to cut €44bn to reduce public debt.
Prime Minister Lecornu faces a united parliament opposing the budget cuts, complicating governance as the public awaits clarity on the direction of economic policy amid rising public debt.
Trade unionist Alexandre Dubois commented, Of course, we'd like more stability in government, but whether it's Lecornu or someone else, we want workers to be truly taken into account. And we need to move away from this logic of short-term economic performance.