Really legit. The owner is french, the chef has spent much time in France, specifically Alsace, as I understand it, and the food was fabulous. My husband and I ate there several years ago on our anniversary--there were only 6-8 parties in the whole night (cold, sleet, end of October), but some were obviously regulars and/or french. I can't remember what we had, but do remember it being difficult to decide as the choices were uniformly tempting. My husband is a wine guy (at that time more of a budding wine guy) and always interested to hear what the wine steward will recommend. I remember the wine steward being very informal in a good way, sitting down with us and having a good sense of humor about wine-speak (you know, chewy, black currant over muted tones of leather).
We do not dine in that price range but 3-4 times a year, for birthdays, anniversary, parent visit, and we have an informal policy of using those occasions to try new places, so we haven't been back. If we could afford it, I think we would be regulars. We still get (just got one) postcards detailing the menu for their special wine dinners (next Tuesday, featuring goose, the wine dinners are usually a food or region or both theme). I only wish they would list the price of the dinner and which wines they will be serving.
I highly recommend this place. Now that I think of it, my Dad is coming to town and, as I said, ours is only an informal policy. I have always read that it is "undiscovered" which probably means quiet; a good choice for an older gentleman.
I am a new poster, have been lurking for a while. I can second the Cafe Matou recomendation. I dont neccessarily know enough to know what is truly authentic. I do know that I have been there five times in the last six months and have been delighted with the food and happier still with the service. A very comfortable room very friendly and open staff. I have send a number of people there and they concur.