More than 1 million people took to the streets across France Tuesday in protest of a new, highly contested labor law as transportation strikes held the country at a standstill.

Riot police armed with batons and shields moved in on more than 200,000 demonstrators gathered at the Place de la Republic in Paris Tuesday in an attempt to quell scattered violence, eventually using water cannons and tear gas to disperse the unruly crowds.

The violence was not limited to Paris. In Rennes, angry protesters threw stones and bottles at police, while police in Grenoble broke up crowds with rubber pellets and tear gas.

Police made 787 arrests around the country -- 488 of them in Paris, National Police Chief Michel Gaudin told The Associated Press. Injuries in the capital were tallied at 46 demonstrators and nine police officers.

Students and labor unions say the law will erode France's cherished workplace protections. Set to take effect next month, it would let companies fire employees younger than 26 without reason in the first two years on the job.

Under the current law, companies are often unable to fire workers unless they are facing bankruptcy or the worker has repeatedly made grievous errors on the job. Firings are frequently appealed in court, where judges often rule in favor of workers.

Unions and the leftist opposition joined in solidarity with the angry students for the one-day strike that shut down many vital businesses and attractions, including air, rail and bus travel and the Eiffel Tower, increasing the pressure on Prime Minister Dominique de Villepin to withdraw the measure.

National newspapers were not on sale at newsstands, and radio and television broadcasts were limited. About a third of public school teachers and other education workers also were on strike.

Before the march in Paris, Interior Minister Nicolas Sarkozy met with police and urged them to arrest as many troublemakers as possible.

As public pressure mounted amid the largest demonstrations yet against the controversial employment contract, cracks appeared within the conservative government over the new law which would make it easier for companies to fire new employees.

In a clear break with Prime Minister Dominique de Villepin, Sarkozy suggested that the measure be suspended to allow talks with unions.

"We have to defend the rights that were won by our ancestors and which the current government is trying to take away," said Maxime Ourly, a literature student who joined the protesters on Paris' Left Bank.

Even with huge marches under way, Villepin held firm. He 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 chances of running for the presidency next year — has appeared increasingly fragile.

Sarkozy, who is also seeking to be the conservative camp's presidential candidate, told a meeting of lawmakers from the ruling UMP party that the law should not go into force as long as talks to resolve the crisis are still possible, his aides said.

Villepin's sputtering effort at reform underscores the dilemma facing many countries in Europe that have lush jobs protections and social safety nets under threat by competition from fast-rising Asian economies with cheaper labor and fewer workplace protections.

According to police estimates, 31,000 marched Tuesday in the southwestern city of Bordeaux, 28,000 in the southern port city of Marseille, 26,000 in the Alpine city of Grenoble, 17,000 in Lyon and hundreds of thousands in nearly a dozen other cities and towns.

Protesters in Paris said they wanted to defend the status quo.

"We are here for our children. We are very worried about what will happen to them," said Philippe Decrulle, an Air France flight attendant. "My son is 23, and he has no job. That is normal in France."

Light rain did not dampen the festive atmosphere, with red union flags and balloons floating over the marchers and stands selling sausages.

The State Department advised Americans in France to avoid areas where crowds were expected to gather and to exercise caution, particularly at night.

France's top five labor union federations also refused Villepin's invitation to meet Wednesday for talks, insisting that he shelve the contract first.

President Jacques Chirac canceled a planned trip Tuesday to the northern port city of Le Havre "in light of events," his office said.

FOXNews reporter Greg Burke and the Associated Press contributed to this report.