PARIS, March 18 — Students joined forces with teachers, workers, retirees, opposition politicians and labor union leaders in more than 150 cities and towns throughout France on Saturday in the largest nationwide protest against the government’s new youth labor law.
A number of public figures joined in, including the mayor of Paris, Bertrand Delanoe; the Socialist party leader, François Hollande; a former culture minister, Jack Lang; and the Communist Party leader, Marie-George Buffet.
The demonstrations were the climax of a week of protests that have shut down dozens of universities and confronted Prime Minister Dominique de Villepin with one of the most serious crises in his 10 months in office.
The giant left-wing C.G.T. workers’ union estimated that 1.5 million people protested nationwide; the Interior Ministry put the total at more than 500,000, with 80,000 in Paris.
Protesters vowed to continue until the government backed down.
Bernard Thibault, the C.G.T. leader, said, "If they don’t listen to us, we are going to have to think about moving to a general strike across the entire country."
Jean-Claude Mailly, the leader of the leftist union, Force Ouvriere, said in a telephone interview after the protest, "The Prime Minister must understand that he must renounce" the labor law "before a true dialogue can begin."
Bruno Julliard, the leader of the student union that first organized the protests, threatened that if by Saturday night, "the government doesn’t withdraw this initiative, we’ll continue."
The protesters want the abolition of a new law — known as the First Employment Contract and set to take effect in April — that allows employers to fire new workers under the age of 26 without cause for two years.
Designed by the government to help ease the crisis of chronic high unemployment, particularly among poor youth after riots last fall in the suburbs, the law is seen by its opponents as a step toward eroding long-cherished employment rights and benefits.
Protesters point out that the law was pushed through Parliament without debate and charge that it is age discrimination. They have dubbed the law the "Kleenex contract" because young workers could be discarded like a facial tissue.
Unemployment in France is at almost 10 percent, and 23 percent of French citizens under 26 are jobless, one of the highest rates in Europe; in some of the major city suburbs, the figure is nearly double that.
President Jacques Chirac appealed on Friday for the marchers to show "calm and respect," and security police officers in riot gear were out in full force throughout France on Saturday.
Authorities were on alert for what they called "professional thugs" after street fights broke out late Thursday in Paris. The police used tear gas and water cannons to quell the violence.
The protests for the most part were peaceful.
Under sunny skies in Paris on Saturday afternoon, the police, anticipating trouble, urged shopkeepers along the march route to shut down.
But the demonstrations started with a party spirit, with balloons and music of the Rolling Stones and Madonna. Protesters were joined by parents with children. Officials from the major unions distributed banners and flags from the back of trucks. Vendors sold hotdogs and kebabs.
"I’m sick and tired of all these phony contracts and I want to protect my children’s future," said Carole Cases, a 43-year-old nurse, with two of her children, from the Paris suburb of Noisy-le-Grand. "They’re trying to dupe the young."
"Villepin, you nonelected jerk," read one banner. In a sign that spring, the season of protests and strikes in France, is coming, another banner read, "Long live spring."
There is little indication that the jobs measure is welcomed by unemployed youth in the suburbs, who are also worried that it does not provide any long-term job security.
"It’s stupid," said Mariam Sidibe, a 17-year-old student of Malian descent from Les Mureaux, a working class suburb of Paris rocked by last fall’s riots, who marched in Paris. "There’s going to be more unemployment."
The police in Paris used tear gas to disperse a small band of youths who thraew bottles and stones at them at the Place de la Nation, on the right bank, the official end point of the protest. Protesters broke shop windows and one car was set afire.
In Lyon, French youths protesting the law clashed with Turks demonstrating against the construction of a memorial to Armenian victims of a 1915 massacre, Reuters reported. The youths shouted, "Fascists!" and "Go home!"
Protests in France
The two sides threw objects at each other and engaged in fistfights. The police used water cannons to disperse them.
In Marseille, the police used tear gas to disperse protesters who replaced the tricolor French flag at city hall with a black and red banner reading, "Anticapitalism and self-management."
In Nancy, about 200 youths blocked railroad tracks for an hour, throwing rocks at the police, who used tear gas against them.
In Rennes, protesters blocked a railway line for about an hour. The police used tear gas to disperse protesters who attacked the local office of the governing U.M.P. party.
The police are still investigating which groups or individuals were responsible for violence in the heart of Paris on Thursday evening.
It was during that protest that antiriot police fired tear gas to disperse bands of youth who threw rocks and bottles at police and burned a newspaper kiosk near the upscale Bon Marché department store. The police also used water cannons against protesters who had set fire to a bookstore and destroyed the terrace of a cafe in the square in front of the Sorbonne.
Extreme right, extreme left and anarchist groups are being blamed for inciting trouble. The youth branch of the extreme right National Front, for example, has distributed antileftist leaflets that say, "Parasites, out of our universities."
About 300 people have been arrested in a week of protests. More than 100 police and 21 protesters have been injured.
In meeting with antiriot police officers on Friday, Interior Minister Nicolas Sarkozy, who, like Mr. de Villepin, hopes to run for president next year, held up a damaged police helmet for the cameras. "Those who do this are not demonstrators, they’re thugs," he said.
Thus far, Mr. de Villepin, whose poll ratings have collapsed recently, has been the main target of criticism by the law’s opponents, and Mr. Sarkozy has said little about its merits.
On Friday evening, Mr. de Villepin met with a group of university presidents who asked him to suspend the new measure for "a period of reflection" of six months.
"We told him that things are getting worse and that next week could prove very risky," said Yannick Vallée, first vice president of the conference of university presidents.
Mr. de Villepin called on protesters to end their blockades and allow nonstrikers to study. "We want students to be able to prepare confidently for their exams and to have the freedom to study," he said.
Well over half of France’s 84 public universities remained either closed or partially closed because of student blockades, according to the Ministry of National Education. On Friday, students demanding the right to study demonstrated in Paris and several other university towns.
Ariane Bernard contributed reporting for this article
By ELAINE SCIOLINO
Published: March 19, 2006