I will be in Paris for 6 weeks this fall and would love to take a French immersion class. Can anyone recommend one, or something as good, in Paris? Thanks very much.

What are you calling an immersion course? Most schools I know simply have options for increasing number of hours of class a week, as you wish. Because you are in Paris you are kind of immersed, anyway, if you take advantage of it, outside of school. Schools often refer to 25 or more hours a week of class as "intensive". Various schools then have a variety of housing options, from none to residence halls and a few may arrange stays with families. If that's what you want, look for one that does that. One school I attended wouldn't allow total beginners to do the super-intensive course, you had to be advanced (guess it wouldn't accomplish that much, don't know).

When I'm in Paris, I try to speak French all the time, anyway, but prefer to stay on my own in a hotel or apt.

So, for private schools that would only offer 6 week possibilities, I have taken at l'Institut Parisien and they were very good. They have a variety of options from a single class to about full-time, I think. Accord is another one I've heard of, although I have no personal experience, and they have lots of options, also, up to 40 hours of class a week. That would be a bit much for me, I need free time to do things in Paris. I think Accord does say they can arrange home stays (some say that but don't have enough available).

these are those schools
http://www.institut-parisien.com/
http://www.accord-langues.com

Institut Parisien says they have some home stays, also. As I said, you have to check on availability if you want that and find out where that stay would take place, but often it may be in the outer suburbs.

You can attend classes every AM at the Alliance Francaise and then "practice" all afternoon and evening in the shops, cafes, etc.
www.alliancefr.org

Thank you both so much...very helpful!

A friend of mine just spent a week in Paris studying with this woman and thought her absolutely fantastic.

http://francoise.duffau.neuf.fr/page12/page12.html

Not sure if this matters to you but l'alliance francaise de paris is one of the least expensive -though very reputable-schools. That's because it is subsidized by the French government to support spreading French language and culture.

Thanks to both of you too.