Chambres d'Hotes are rooms in private houses - a Google search for that name will yield many many - not much in Paris but throughout the countryside and in smaller towns IME. If you have a car you will be able to drop in to many unless traveling during the peakest of peak seasons.

I am not clear on what you are asking for, it sounds like a rooming house. There aren't that many of those, they can be hard to find, and would be in big cities (and probably mainly for students, interns, things like that). But there are B&Bs in the rural area and now a few in the big cities, if you really want that. There are a few websites with B&B listings in France (in rural areas they might be called Chambres d'Hotes.

here is one website for Paris B&Bs http://www.parisbandb.com/

But there isn't much point in my naming a lot of stuff if you don't even know where you want to do this, so why don't you narrow it down first to a city where yo uwant to be, or area. And what time of year, and for how long, that is really important to know.

There are numerous websites for private vacation apartment rentals, tons of them. www.vrbo.com is just one of them

If you've never done anything like that before, that can be a bit daunting to think of all the things to ask about and watch out for.

As for your statement about renting an apartment without a reservation, I can't imagine where you heard such a thing. Maybe a room in a hostel, but no vacation apartment will be possible without a reservation.

Here is something posted a while ago.

http://www.fodors.com/community/europe/renting-gites-through-the-gites-de-france-web-site.cfm

Stu Dudley

Not even airbnb.com will let you rent without a reservation.

Look at http://www.homelidays.com/, homeaway.com, airbnb.com for suggestions on places to stay.

We have stayed in several countries and cities using the above sites, plus more. If you need more information, email me: jkbritt@hotmail.com