By Caroline Wyatt
BBC News, Paris
Tempers flared again in Paris on Thursday, pitching riot police against students in yet more violent clashes.
Some youngsters had come in from the surrounding suburbs looking for trouble, and they found it on the streets of the Left Bank.
By the Sorbonne, in the intellectual heartland of France, a bookshop was set alight, with rioters smashing up a cafe and using the chairs as missiles against police.
University areas of Paris became a no-go area
Anything that came to hand, from street signs to rocks, was hurled at police officers, as police and youths, some of them masked, fought running battles in this latest stand-off.
Water cannon and tear gas dispersed some, for a little while. But soon they were back. Other youngsters taunted the police, who tried to stand firm behind their riot shields.
Elsewhere, police patience was at an end, as they dragged some protesters off by their feet. One policeman could be seen beating a fallen protester with his riot baton.
Government under pressure
By mid-evening, the area around the Sorbonne - France's elite university - had become a no-go area for anyone not involved in the fighting. But eventually, as midnight neared, the area calmed and cleared.
Yet this had all started peacefully earlier in the day, when some 120,000 students in Paris gathered for a march, and up to 250,000 across France as a whole.
Their anger was focused on a new job contract being brought in by the government to tackle chronic unemployment. One in four young people here is without work.
The new contract will make it easier not just to hire but also to fire those under 26, which these youngsters see as a threat to their future and any hope of the kind of jobs for life many of their parents and grandparents enjoyed.
Antoine, a 23-year old economics student, was marching arm in arm with his friends, holding aloft banners expressing their anger.
For him, the purpose of the march was clear.
"The government of Dominique de Villepin is trying to take away our stability and our future," he said. "We want to keep secure jobs and be employed."
These demonstrations are growing every day, putting more and more pressure on the French government, which may soon be forced to listen to the growing anger on the streets of France despite Dominique de Villepin's stated intention of holding firm. Trade unions are planning even bigger demonstrations across France on Saturday, when they hope a million people will join in.
In the Marais district, students studying English had made banners in both languages, so their message could be understood both at home and abroad. "Mr de Villepin, you are not king", read one. "My kingdom for a job contract," said another.
Battle for future
This is the future French elite, top students who should be full of hope for the future. Yet today, these youngsters admit to feeling a real sense of gloom about their prospects in France, where unemployment has stayed stubbornly high for years.
Jacques Heilmann is studying English, but worries about finding a job when he graduates.
Anger is focused on a new job contract to tackle chronic unemployment
"Unemployment in France is huge, and we feel let down, and we feel there is nothing to hold on to," he said. "We simply don't know where we are going."
On Thursday night, France watched on as the peaceful marches turned into running battles on the streets of central Paris in scenes more reminiscent of November's riots than images of May 1968 conjured up for some by the sight of students trying to take the Sorbonne.
And for many there was once again a sense of a nation at war with itself over how best to face the future.
The economy is the main battleground: pitching those who want change, against many of the young who feel betrayed, and long for the old certainties of jobs for life and guaranteed pensions - and a generous welfare system.
In other words, all the benefits enjoyed by the generation which took to the barricades themselves in France in May 1968, yet who can no longer promise the same for their children and grandchildren.