Trade unionists and students protesting against youth unemployment vowed to hold street demonstrations this week after riot police fired teargas and stormed the Sorbonne in Paris at 4am on Saturday, ending a three-day occupation.The officers dragged out 200 students who had taken over the university for the first time since 1968. The prime minister, Dominique de Villepin, planned to defend his "first employment contract", which gives employers the right to let staff go after two years, and which sparked the protest. The Sorbonne will shut for a week to be cleaned.