By Brian Love

PARIS (Reuters) - The French authorities sent in private rubbish collection trucks to clear piles of rotting garbage from Paris streets on Friday and told striking public sector workers they would not be allowed to disrupt Europe's soccer championship.

The eyes of the continent are on France as the Euro 2016 tournament kicks off later in the day, with 1.5 million foreign fans expected to join millions of French supporters for the month-long sports festival.

"All the rubbish will be cleared up, starting now, today," said Paris Mayor Anne Hidalgo, adding that about 50 trucks had been dispatched overnight and 30 more on Friday morning to rid the city of waste left piled up by striking workers.

"It will take a few days obviously."

The waste treatment workers' strike is one of several by public sector employees angry at government plans to make hiring and firing easier with a revamp of labor law, which President Francois Hollande has repeatedly said he will not withdraw.

Wary of damage to France's international image, Transport Minister Alain Vidalies condemned plans by Air France pilots to strike for four days from Saturday and said train drivers would be forced to ensure public transport for fans if needed.

The soccer tournament is supposed to showcase the ability of a country still smarting from deadly militant attacks last November to handle a major international event smoothly.

"If requisitioning is required ... we'll do it," Vidalies said. "There will be no more negotiating. There's no longer any reason to continue the strike if it's not for political reasons."

Public-sector waste treatment staff who have been on strike for days have vowed to continue the protest into next week. Workers at the state-owned SNCF railways were on strike for a tenth day on Friday.

Air France said it hoped to guarantee about 80 percent of flights on Saturday when pilots start a four-day stoppage over pay cuts. One in four medium-haul flights would be scrapped and about one in 10 scrapped on long-haul and domestic routes.

Vidalies said the government would not tolerate any form of illicit protest such as occupation of railway tracks, a ploy used occasionally in recent days to bring transport to a halt.

One big concern was threats by some unions to disrupt train links between Paris and the suburban 80,000-capacity Stade de France stadium where France plays Romania in the tournament opener on Friday night.

"This is an action against France and the French people," the minister told Europe 1 radio.

Fans were urged to turn up early at Stade de France, where gates would open three hours before a 1900 GMT kickoff, with the SNCF promising to ensure high-frequency rail connections at crunch moments. Local media said SNCF executives were being drafted in to replace striking train drivers.

Asked if images broadcast worldwide of rotting rubbish would also compromise Paris's bid to host the 2024 Olympics, Vidalies quipped: "I didn't see any hordes of rats on my way here."

France is deploying nearly 90,000 police and security staff to head off any risk of violence or repeat of attacks in which Islamist militants killed 130 people and injured hundreds last November in Paris and outside the Stade de France.

Police in the southern port city of Marseille stepped in to halt skirmishes in the early hours of Friday between locals and England supporters who spent the night drinking alcohol outside pubs in the lively Vieux Port area of the city. [nL8N19217M]

Almost 90,000 people danced overnight at an incident-free music concert to celebrate the start of the Euro tournament at the foot of an Eiffel Tower, lit up in the French colors of blue, white and red for the occasion.

(Additional reporting by Dominique Vidalon, Emmanuel Jarry and Myriam Rivet; Editing by Paul Taylor, Susan Thomas and Peter Graff)