Originally Posted by MDSD
Also keep in mind that Paris will not only be cold, but the days will be short (daylight ~ 8:30-4:30-ish), limiting your day trips. This would be a great week to stay pretty much in Paris with its great museums uncrowded (the ones open during the holidays!), and enjoying the cafes.
Versailles could be easily done, perhaps the champagne area of Reims; other that that, I'd spend the time exploring Paris.
I would have responded sooner, but I've been in PARIS!
Chartres is another easy day trip - but I wouldn't go there unless you woke up to a sunny day. The stained glass is much more spectacular when the sun is out. If you are lucky, Malcomb Miller will be there doing a tour - he has spent his life studying the windows - shortly after noon and mid-afternoon every day but Sunday (when he is not lecturing elsewhere as he sometimes does in the winter). I agree with the above, however, that you could easily spend your entire time in Paris and still feel you had many things left unseen.