Also Seen at Hotel de Ville: IUFM of Paris protest

The plaza in front of the Hotel de Ville was also used several times as a "call to action" center for manifestations (protests) and collecting signatures for a variety of petitions.
The students below are professors in training (I don't know if they are in training to teach secondary school or at a University level--my guess is the former) who were protesting some changes to the way the teacher training programs at the University were being organized and administered.
Protests are not very effective. They happen way too often in Paris to have much of an impact.