My partner and I spent 5 days over Thanksgiving, stayed in Polanco and had some excellent meals. We were visiting friends who are Mexico City natives, so between their favorites and places I read about on CH, we had a nice variety. I hope this will be helpful to future visitors.
I can recommend the following:
Wonderful Basque/Northern Spanish. Loved the division of the menu into modern and traditional dishes. We had some of each, and all were superb. Best non-Mexican meal we had.
Touristy but not a tourist trap. Very good traditional food, nice decor, LOUD, lots of large groups, mariachis, huge frozen Margaritas with very little alcohol, dirt cheap for the quality and quantity.
DO (Denominacion de Origen)
Another Basque/Galician place, pretty traditional. Had a wonderful whole fish baked in salt crust. Reasonably price and nice atmosphere.
Fonda del Refugio
Wonderful traditional Mexican in Zona Rosa. We got a tour of the kitchen and saw how they make the tortillas from scratch (beginning with the raw corn), best tortillas you will ever have. They make their own sausages, etc. This is not to be missed.
Modern Mexican in a lovely setting. Very creative food, excellent service, a casual but classy place.
San Angel Inn
Gorgeous hacienda located in Altavista (worth a taxi ride from Polanco). We went on Sunday afternoon, when the place is filled with family groups. It is hugely popular. The food was surprisingly delicious as even the friends we went with had said it was good but not great. They mix Mexican with French. For my main course, I had calf brains with tomatillo sauce. Wonderful! There are plenty of more conventional choices for the less adventurous. The Margarita was the best I had on this trip.
We loved Mexico City and look forward to returning.