Paris Insider's Guide
We were at the American Library of Paris the other day, and C happened to pick up a copy of the Paris Insider's Guide 2010. At first I thought it was just another random guide, but after flipping through it, I realized it was actually a really handy little booklet, even for the seasoned expat.
It has several different sections, covering everything from safety info to expat organizations & clubs to metric conversions. There are pages that list all of the different marchés in Paris and others that give hints about how to start & end a French letter or how to make friends with your building's concierge. There's even a short how-to for attending a French wedding.
C was particularly interested in this page, which mentioned various chalk-marks burglars could leave on doorways when scouting out future apartments to break in to:I'm not sure how "real" this actually is, but it was still interesting to learn about anyways - and now you'll know just in case to erase any random chalk marks you find on your door!
Portions of the guide can be downloaded on their website here.