Critics say the law, which makes it easier to fire young workers, will erode workplace protections.
PARIS -- In the hundreds of thousands they marched, the latest generation of French street protesters, some with "Non" painted on their faces and bearing red union flags and banners.
But in parliament, away from the angry hubbub rising up from cities and towns across the country Tuesday, Prime Minister Dominique de Villepin stood firm -- there would be no backing away from a law making it easier to fire young workers.
More than 1 million demonstrators poured onto French streets, and strikers shut down the Eiffel Tower and disrupted plane, train and bus services in the largest nationwide protests so far against the new measure.
Scattered violence erupted in Paris, and riot police used water cannons and tear gas to disperse several thousand youths who pelted them with stones and bottles after an otherwise peaceful march.
Police made 787 arrests around France, national police chief Michel Gaudin said. Injuries in the capital were tallied at 46 demonstrators and nine police officers.
Interior Minister Nicolas Sarkozy even invited some 200 police officers, some still wearing their protective gear, to the Interior Ministry for wine and snacks.
"I'm proud of you," he said. "Mission accomplished."
Still, the heightened pressure, with unions, students and the leftist opposition joined in solidarity and more violence erupting in Paris, opened cracks in the ranks of a government facing elections next year.
In a clear break with Villepin, presidential hopeful Sarkozy suggested suspending the law to allow for negotiations.
Police and organizers' estimates for the number of marchers varied greatly, but both showed that the protest movement is growing.
Police said 1,055,000 people took part in more than 250 protests nationwide, including 92,000 people in Paris. The organizers' total was closer to 3 million, with 700,000 at the march from the Left Bank.
Students and labor unions say the labor law will erode France's cherished workplace protections. Set to take effect next month, it would let companies fire employees under 26 without reason in the first two years on the job.
Under the current law, it is difficult to fire anyone unless the company is facing bankruptcy or other dire financial difficulties, or if a worker has repeatedly committed grievous mistakes on the job. Many firings go to the courts, where judges often rule in favor of workers.
Villepin told parliament that he was open to talks on employment and possible changes to the law but did not say that he would withdraw it.
"Only in action will we convince all of the French that tomorrow can be better than today," he said, loudly heckled by opposition politicians.
Villepin says the greater flexibility will encourage companies to hire young workers, who face a 22 percent unemployment rate -- the highest in Western Europe. But as protests have grown, his government -- and his chances of running for president next year -- have appeared increasingly fragile.
Sarkozy told lawmakers from the ruling party that the labor law should not go into force, so that talks to resolve the crisis can take place, his aides said.
Villepin's sputtering effort at reform underscores the dilemma facing many European countries that have expensive job protections and social safety nets under threat by competition from Asian economies with cheaper, less-protected workers.
The nationwide strike -- the first time that unions had ordered walkouts in solidarity with students spearheading the protests -- slowed train, plane, subway and bus services to a fraction of their normal levels.
The Eiffel Tower was closed, its employees said. Some elementary and high schools also were shut as teachers walked off the job.
National newspapers were not on sale at newsstands, and radio and television broadcasts were limited.
The State Department advised Americans in France to avoid areas where crowds were expected to gather and to exercise caution, particularly at night.
"We are here for our children. We are very worried about what will happen to them," said Philippe Decrulle, an Air France flight attendant at the Paris protest. "My son is 23, and he has no job. That is normal in France."