Police raided the university just before 4am Paris time and within 10 minutes evacuated about 400 student activists, ending the drama.
Sorbonne had been joined by many other universities throughout the country in protest action on Friday.
Police used teargas and batons to push the students to the exit, an AFP correspondent said. The students had tried to confront the anti-riot police, forming a human chain and chanting "peaceful resistance".
Amid scenes of panic some of the protesters tried to block the police advance by hurling tables and chairs at them.
The square outside the university soon emptied after the raid and was sealed off by a double row of police officers, according to AFP.
More police proceeded up a nearby street to disperse about 200 youths still milling around there.
Police had entered the Sorbonne building after a request from the chancellor of Paris Universities Maurice Quenet, the police headquarters said.
Night of violence
Earlier officers, launched teargas at protestors after coming under attack from students who hurled oil cans, fire extinguishers and seemingly anything they could lay their hands from upper-storey windows of the university block.
Witnesses have said police earlier used batons to beat some students in scenes reminiscent of those of the 1968 student riots that shook France and brought the government of the day to its knees.
Paris's Socialist mayor, Bertrand Delanoe, said in a statement he was "deeply concerned" about the use of force by police against the student protest. He described the protest as having been passing off peacefully.
Employment contract
Students, along with the country's powerful unions, are trying to force the government to withdraw a new labour law making it easier to sack young workers.
The “First Employment Contract” is a two-year contract for under 26-year-olds which employers can break off at any time without explanation.
Student leaders said more than half of the country's 85 universities were totally or partially paralysed by protests, but Education Minister Gilles de Robien said the figure was only 11 - with small-scale disturbances at a further 20.