Where is it - if it's in Paris and includes airfares it's probably ok
Yes I would consider that to be a lot of money. Is it the Savoy? Might be worth it there, otherwise shop around for a better deal. My local Harvester offers Christmas Day lunches for around £40pp; they don't do dinner though. Are you staying at the hotel or just planning to go there for the meal?
Hmmm. Definitely shop around to get a better deal. That hotel is simply milking the occasion and the price is unreasonable. For that money, I would expect to stay there as well.