Como Tale vu, Abbigail,
Lucky you!
I'm not sure about calendars etc as I never pay special attentions.
However, if you're in Paris on 3rd Feb 2013 (first sunday of the month), just pop into Orsay Museum (free ticket). I am very sure that you will like it.
Musee d'Orsay
Next, I noted that you're going to the north-eastern France. I wonder whether you're going for a military trip?
The famous D-Day celebration is in June and you can see a lot of alliance force (of course, they aged a lot) driving in Jeep etc. A huge and quite impressive event. But, sorry it's in JUNE.
Having says that Mt-St-Michael is quite unique and I enjoy it too. However, there is no need to go until the Normandi beach.
Going to Mt-St-Michael, likely you'll pass by a city called Rouen.
There is a cathedral called Notre Dame cathedral (on hindsight, every city in France has a cathedral and the name of the cathedral is always called???? Yup, no prize in guessing right: Notre Dame)
I like this Notre Dame because a famous artist called Monet had stayed and painted many many view/time of the cathedral. (which I saw in Orsay Musee too).
And, as I was on my return trip to Singapore after visited Normandi D-day, I conveniently stopped over at Monet's home which is in Giverny. (you see, instead of driving into Paris, I drive directly to airport and return the rental car there and fly back to SGP). Here, his famous painting of Lily pond you'll see and also if you're in the right season.... incredibly beautiful poppies field - red red and red.... (happy, happy)
I'm not sure how long you're visiting or how you intend to stay in which city for how long so can only reply based on what you'd wrote.
Let me know a bit more of your plan (driving? go with friend or family?) and we see how far we can go?
Bon Voyage.