Students clashed with police outside the Sorbonne University, rampaging after a protest against a new jobs law that was part of nationwide demonstrations drawing about 500,000 people. More than 150 people were arrested. Police turned water canons on hundreds of protesters who had moved across town to the Sorbonne, torching the entrance of a nearby Gap clothing store and dismantling a section of a barricade erected to keep protesters at bay. Four cars were set ablaze in the protest frenzy, police said. A McDonald's restaurant was attacked along with store fronts at the close of the march in eastern Paris. Police were seen throwing youths to the ground, hitting them and dragging them into vans. Protest organizers have urged President Jacques Chirac to block a new law that makes it easier for employers to fire young workers. They demanded an answer by Monday - then they will decide whether to continue protests that have paralyzed at least 16 universities and dominated political discourse for weeks.