French unions and student bodies called on Monday for a general strike and protest marches on March 28 to pressure the government to withdraw a job law they say will create insecurity for a generation of young workers.
Students raise their hands as they vote to continue their strike in Toulouse
"All the unions are calling to make March 28 a day of demonstrations, strikes and work stoppages," said Rene Valadon, secretary of the Force Ouvriere union, after a meeting of France's main unions, student and high school groups.
Another union leader, Gerard Aschieri of the Federation of United Unions, told Reuters that public and private workers would go "hand in hand" during the day of action.
Villepin stood by his contested youth jobs plan Monday, as an ultimatum for its withdrawal passed with no hint of concession and unions promised a new day of nationwide protests next week.
"Laws of the Republic, voted democratically by parliament, must be respected," Villepin said in a letter sent to members of his centre-right Union for a Popular Movement (UMP).
He held meetings with students and employers on Monday to discuss their concerns and promote the law.
Support from president
The prime minister won support from his close ally President Jacques Chirac, to whom opponents of the CPE appealed earlier to use his influence to have the contract abandoned.
Chirac said that "it is essential to take steps for youth employment, and the CPE is a sign of this determination on the part of the government and parliament. Questions and doubts are being expressed and that is wholly legitimate ... but they must not lead us to do nothing."
French Prime Minister Villepin, foreground, at the start of a meeting with students and unemployed people
Conceived by Villepin as a tool for bringing down France's high levels of youth unemployment, which is as high as 50 percent in areas hit by riots late last year, the CPE was adopted by parliament earlier this month as part of a wider equal opportunities bill and is now waiting to be written into the statute books.
But the measure has sparked a powerful opposition alliance of unions, students and left-wing parties, who say it is a charter for exploitation by employers and a breach of hard-won social rights.
Three days of nationwide demonstrations over the last two weeks have drawn hundreds of thousands onto the streets in protests that on Saturday ended in several hours of running battles in Paris between police and a small minority of rioters.
Most of the country's 85 universities remained partially or totally shut down by student strikes on Monday, and for the first time more than 300 secondary schools across the country were also affected.
Students at the elite Science-Po political science school voted to go on strike to protest against the CPE.
Protesters clashing with police in Rennes, western France
In addition to next week's day of national protest, student organisations have urged supporters to stage protests Tuesday and Thursday of this week.
"There is no risk of things tailing off, because we have sizeable reserves among the secondary school and university students. We can step up the mobilisation. We have got such a dynamic behind us we are bound to make the government give way," said Bruno Julliard of the UNEF students' union.
Crisis for Villepin
Opposition to the law has provoked a crisis for Villepin, which could harm his chances of running for president in 2007 and damage the UMP party. Opinion polls show his popularity has slumped in recent weeks and a poll on Monday showed that 60 percent of French voters are against the law.
Large rallies can make or break governments in France. Protests in 1995 badly undermined the then conservative Prime Minister Alain Juppe, who lost snap elections two years later.
Critics within his own ruling UMP party have dubbed the CPE Comment Perdre une Election -- How To Lose an Election.
In a sign of worsening tensions, hospital officials confirmed that a trade unionist is in a coma after being hurt in clashes with police at the end of a mass rally in Paris on Saturday.
The 39-year-old man was hospitalised after being injured in the face during clashes between police and protesters at the Place de la Nation in eastern Paris, police said in a statement.
He was in serious condition, it added.
The Paris prosecutor's office has opened a preliminary investigation, the statement said.