PARIS, NOV. 12 -- More than 100,000 French high school students, backed by parents and teachers in their demand for more government spending on schools, took to the streets of the capital today in the biggest demonstration yet of a burgeoning grass-roots campaign for higher-quality education.

The massive march across central Paris from the Place de la Bastille toward the fashionable Champs Elysees was orderly for the most part, but several hundred participants broke away from the vast throng about two hours after it set out and smashed windows, looted stores, set fire to cars and attacked policemen with rocks and bottles.

At that point, French authorities ordered the demonstrators to disperse as police moved in to suppress the violence with tear gas and water cannon. The turbulence continued into the evening, leaving at least 40 police officers and an unknown number of demonstrators injured. Authorities said about 20 youths were arrested.

Despite the turmoil, a number of student leaders were able to meet separately with President Francois Mitterrand and Education Minister Lionel Jospin, and they said afterward that they received a sympathetic hearing of their demands.

Following the meetings, Jospin announced that an "emergency plan" to improve education and safety in the schools would be put into effect, but he provided no details.

Jospin, who is considered the government's second-ranking minister and who was filling in today for traveling Prime Minister Michel Rocard, had announced recently that the education budget would be raised 9 percent in the coming year to $43 billion, surpassing the country's defense outlay.

But student leaders had complained that such program funding would take years to show results and have been demanding an immediate increase in the number of teachers and other personnel to improve the quality of instruction and counteract a rising level of indiscipline and physical violence in public schools.

Today's huge rally -- and smaller similar gatherings in cities throughout France -- culminated weeks of swelling student demonstrations protesting poor security, cramped classrooms and a shortage of teachers that seem to have taken the government completely by surprise. While the outburst has shown no sign of producing widespread urban paralysis -- as occurred more than two decades ago when violent student protests drove president Charles de Gaulle from power -- the momentum of the campaign and the history of such discontent spreading to key economic sectors clearly has the Socialist government worried.

But unlike the 1968 rebellion, which was bathed in Marxist ideology as middle-class students renounced their privileged upbringing and joined workers in assailing bourgeois ethics, the current turmoil has been instigated by youths from lower-class, often immigrant families who seek economic success and escape from suburban ghettos through higher education.

Despite the already high levels of public spending on education, the number of new teachers and facilities has not kept up with the soaring numbers of students, many of whom began to camplain loudly in recent months about what they view as the deteriorating quality of education brought on by insufficient resources.

A series of minor student strikes and protest rallies against crowded and unsafe school conditions quickly snowballed several weeks ago after a 15-year-old girl was raped by four youths in a high school lavatory in the Parisian working-class suburb of St. Ouen. Since then, protesting students have been joined by their parents and teachers in demanding immediate action by the government to improve the system.

At today's Paris march, some protesters carried placards urging the government to use money earmarked for the French military effort in the Persian Gulf to hire new teachers and supervisors for their schools. About 8,000 French troops have been dispatched to the gulf since Iraq invaded Kuwait three months ago.

Mitterrand, who launched his second seven-year term in 1988 proclaiming that he, like President Bush, wanted to make education his top priority, expressed support for "all demands bringing more democracy to the schools." A presidential spokesman said Mitterrand told a group of 20 student leaders that their demands for more state spending on schools "deserve to be considered as quickly as possible."

Nasser Ramdan, one of the students who organized today's march and who met with Mitterrand, said the president was unequivocal in his support for the student demands. "It's now up to Rocard's government to fulfill its responsibilities," he said.