The owner just passed, but you might check shakespeare and co bookstore (google it), it is a really famous english bookstore, that was run by this crazy old man for a long time. They had some guest rooms upstairs, and even if they were full he was known for letting travelers sleep in the shop. But, he died, yesterday from what I can tell.
uhhh, I have friends in Paris, but I probably wont pass on contacts to you. sorry, nothing personal.
Camping out anywhere is fine. There are a lot of old homebum camps down by the canals, and as long as you arent rich, and arent sketchy, the bums are kind enough. And if you are rich, or sketchy, I hope they roll you in your sleep. I was always housed up, but I know people have camped right beneath the Eiffel tower, or just about anywhere France is known for being good to the poor.
You can check
anarchist yellow pages or
squat.net for some more ideas, and there are a few other threads on here, but Paris sucks. Which you probably already know, since you were reading those other threads already.
Mid January wont be fun on the streets either, weather is shit round here. I'm quite close to Paris now (ehhh, maybe 250km), and its storming like hell all day long.
uhhh, I dunno, couchsurfing?
Get the hell outta paris?