Paris does a great job of decorating for the Christmas holidays, and there are often special foods available. About the middle of the month a skating rink goes up near the city hall, and last year there was also one in--IN--the Eiffel Tower. Department stores dress up their windows in a feast of colors and lights. Christmas concerts will be scheduled at churches, as well as other places.

After talking to my husband about this :) he remembers that the Croque Madame had an egg on it and no ham. But that might have been a request of ours rather than the Real thing.
So don't take my word on this :)

Melanie,

My hubby and I are going to Paris in 5 weeks and he is a veggie too (sorry, I'm only veggie about 1 meal a day w/him)

I looked for Thai, Moroccan, Chinese and Indian places on http://www.reservethebest.com
You can view the menus and get a feel for offerings.

We are going to try a Thai place,Blue Elephant, on Rue de la Roquette.

Also, I believe Yod Peng is "tofu" on the menus.

Will let you know if we come across any great places when we are there in late October.

I second the suggestion of Le Grenoir de Notre Dame. Terrific veg. restaurant and wont break the bank

Le Sept/Quinze in the 15th near UNESCO very close to the 7th, at 29, av. de Lowendal, had 2 vegetarian main dishes on its lunch menu last May, one of them pasta and the other one risotto. Some of the first courses were also vegetarian. It was delicious.
Also, on one of the avenues that go south from the 7th, I think it was avenue de Segur, and reach Métro Sévres-Lecourbe, there was, on the left side, some restaurant/coffee shop that served organic vegetrain food. It has an English name and the menu is also written in English, but I just couldn't find its name afterwards. I might try again and post its name if I find it.