I chose a program through AIFS that was in Paris and taught in conjunction with the Sorbonne (CCFS). This was a great program. AIFS basically did everything for me, they registered me, they even got me a metro pass for the month. I did decide not to live in the student housing (a decision I am so happy I made), and found an apartment to rent for the month on Airbnb for much less than AIFS was charging for housing for the month.
That was the right decision for me, as I wanted more privacy and a more "home-y" atmosphere. I was worried, (rightly, it turns out) that the AIFS housing would be all 18 year olds who wanted to party. It was! And if you are in a foreign land and wanting to be involved and make friends, that might be the right decision for you. I knew I did not want a random roommate sleeping 3 feet from me for 5 weeks. That would have made me miserable. So for me, Airbnb was the right solution. I found an amazing apartment in an old building with beautiful exposed beams. My landlord lived upstairs and gave me great information about the area. I even had a young French couple across the hall that invited me over a few times for some great home cooking, wine and wonderful (if stilted) French conversation. I had a kitchen so I could cook and going to local markets and grocery stores made me feel like a local!