What does the word "University" bring to your mind? For me, it is the sprawling campus. When I say campus, it is the greenery associated with universities. With a lot of open space, it can be used for activities that fosters either interactions or introspection. But that is not the case with the universities in Paris.
Primarily, Paris is a very small city which is densely populated. Anybody looking for an apartment in Paris knows how difficult it is to sign a lease. For each opening, there are many people queueing with applications. In a densely populated city with many buildings, it is difficult to find the open space required for a sprawling campus.
"Our campus are the jardins(gardens namely Tuileries, Luxembourg etc)". A friend playfully remarked. An ignorant me couldn't comprehend the message. For me, Cite Universitaire has an excellent campus. When in doubt, always ask questions. You always get answers. Oversimplifying the response, Cite Universitaire is no university. It is a bunch of hostels for students. Students from different universities in Paris can apply for an accommodation here.
If you analyze this further, this is good too. Instead of students going to just one university flocking together, this provides a chance for them to interact with students from different university. The more diverse the views of your peer group are, the more open your mind becomes. Don't you agree?