PARIS - Several hundred masked protesters hurled objects at police in Paris on Tuesday as the latest demonstration against disputed labour reforms in France descended into violence.
The clashes erupted as the international spotlight was turned on France as the host of the Euro 2016 football championships, which have also been marred by violence between fans.
Strikes closed the Eiffel Tower and disrupted transport links as tens of thousands of fans pour into the country for Europe's showcase football event.
Authorities made six arrests and at least two people were hurt in the Paris unrest, according to a reporter at the scene, as demonstrators stormed a building site and began to hurl wooden palettes at riot police.
Pictures showed one man being led away by officers in riot gear with blood streaming from a wound above his eye, his white T-shirt splattered with blood.
The strike is the latest in months of industrial action that has seen air and rail transport severely disrupted, fuel shortages and rubbish piled up on the streets of Paris.
"I've been to all the demos since March because I want to live in dignity, not just survive," said Aurelien Boukelmoune, a 26-year-old technician marching in Paris.
"I want the reforms to be withdrawn, pure and simple. Only then will it stop. For the government's sake, they should withdraw the law, otherwise we'll block the economy."
With France on high alert due to the threat of terrorism during Euro 2016, overstretched security authorities feared the demonstrations could turn violent and banned 130 known troublemakers from taking part.
The terrorism threat was thrust back into the spotlight after a man claiming allegiance to Islamic State (IS) jihadists killed a policeman and his partner at their home in a northwestern Paris suburb late Monday.
The latest in a wave of protests that began in March coincides with a French Senate debate on the reforms, which are aimed at making the job market more flexible and reducing high unemployment but which critics see as too pro-business.
President Francois Hollande's Socialist government has voiced hope the latest day of protest will be a last stand for the movement.
But Philippe Martinez, head of the far-left CGT union that spearheaded last month's blockades of fuel depots and an ongoing rail strike, predicted a "very strong mobilisation".
The CGT laid on more than 600 buses to transport demonstrators to Paris and said it hoped to attract more support than in March, when it claimed 1.2 million people took to the streets.
Authorities put the March figure at 390,000.
For Tuesday's protest, Paris police chief Michel Cadot said he expected "maybe more than 50,000 demonstrators" in the capital alone.
Two further protest days are set for later this month.
At a time when the French capital would normally be reaping the benefits of high-season tourism boosted by the football, the demonstrations have dampened the flow to the world's most-visited city.
Several staff at the Eiffel Tower went on strike, leaving insufficient numbers to open the monument safely, according to its operator, Sete.
Adding to the climate of discontent, rail workers continued strike action to protest working conditions. They were joined at the weekend by a minority of Air France pilots.
The pilots' strike, which affected about one in five flights according to the airline, was set to end on Tuesday but the rolling strike at national rail company SNCF was in its 14th day.
The actions have further depressed France's tourism sector, already hit by the November jihadist attacks in Paris.
The government sparked fury when it forced the contentious reforms through parliament without a vote.
The opposition-dominated Senate is expected to push for changes more favourable to employers and will wrap up its debate on June 24, with a vote four days later.
If the two houses of parliament fail to agree on the legislation, the lower house will have the final say -- and Prime Minister Manuel Valls could again ram the bill through.
While rejecting union demands to withdraw the bill, the government has watered it down, notably by scrapping a cap on severance pay.
The CGT has signalled it may drop its demand for an outright withdrawal of the bill.
Mr Hollande, who faces a re-election bid next April, had hoped the signature reform would reverse his approval ratings, which are among the worst of a modern French leader.
Polls show public opinion could be turning against the union action.
A survey published on Sunday showed that 54% of people did not agree with the strikes.
A similar poll three weeks ago suggested that a majority was in favour.