Here are some pics of the "Place de la Sorbonne" which is the "Sorbonne square" in front of the Uni, but they have put this "wall" all around the student quarter. This walls are mainly due to the 'casseurs' unfortunately. Only students are allowed eventually to get in after showing your student ID, but we must be "escorted" by one of those guys below, and explain why we need to get in.
On the wall (have no idea how they were able to write on it, as I think -or I thought- that the police was always in front of it), it is written: Police everywhere, Justice nowhere.
Sorry for the poor quality of these pics but I was in a hurry, and i took them while I was walking.