Opposition groups said on Saturday that they would join students and unions in more mass protests set for April 4 despite the French president's speech on Friday, which aimed to defuse a confrontation over the law that has put pressure on Dominique de Villepin, the prime minister.
Meanwhile de Villepin admitted in an interview to making errors in the handling of the youth labour law and expressed regret for misunderstandings.
"There is misunderstanding and incomprehension about the direction of my action. I profoundly regret it," he told Le Journal du Dimanche. Asked if he had made mistakes, he replied: "Of course, in all political action there is some error."
Under the law employers can fire workers under 26 without reason during a two-year trial period. President Chirac said he would sign it and then introduce a new one to create a one-year trial period and make employers justify any firing.
But Chirac missed the point of the student protests, Dominique Strauss-Kahn, the former Socialist finance minister said.
"There is misunderstanding and incomprehension about the direction of my action. I profoundly regret it"
Dominique de Villepin,
French prime minister
"They don't want just a trial period shortened from two to one year. They want their work contract to be the same as other workers," he said.
Laurence Parisot, head of the employers' association MEDEF, backed Chirac's move and urged the government not to give in on its plan to let employers give reasons for firing only verbally.
Business leaders fear that more protests could damage France's image and harm investment and tourism, especially since the unrest has erupted so soon after rioting by youths in the poor suburbs around France's main cities late last year.
"This confusion cannot stop the crisis," said the left-wing daily Liberation, criticising Chirac for signing the law but asking employers not to use it until it has been modified.
Dominique de Villepin has
admitted making mistakes
Violence broke out at some protests overnight, with demonstrators wrecking the Paris office of Pierre Lellouche, a member of parliament for the ruling UMP party. Police said they made around 100 arrests in the French capital.
Protesters, who numbered more than a million last Tuesday, say the First Job Contract creates "Kleenex jobs" that make it easier for firms to dispose of young workers.
Youth unemployment stands at 22% in France, far above the 9.6% national average.