Sciences Po Paris (IEP)

I enjoyed staying with a French family, but the experience can be challenging. Generally, you experience far more of the culture that way, with ample opportunities to improve your language skills, and learn many of the small things (table manners, talking to children vs. adults, etc.) that translate into real cultural fluency. At the same time, most of us were used to living on our own, and adjusting to family life can cause frictions. I'd stay with a family again, were I to repeat the experience, but would probably spend half the year there, and the other half in independent lodgings (like the Cite Universitaire).

Sciences Po is a rather unique institution in many ways, and has played an important role in French politics for many years. Academically, the program was challenging, but what you got out depended entirely on what you put in. The entrance exams can seem onerous, but I'd recommend giving it a shot if you're interested.