Nathalie's place was just perfect, highly recommend. I stayed for two weeks for a work trip and would absolutely stay again. The apartment is clean, simple, and tastefully decorated. The bedroom is quite functional, with a window that opens, desk, twin bed, ample closet and drawers. Nathalie installed a wifi extender while I was there, so video calls generally worked well, although sometimes I took them from the living room if it was coming in and out. Kitchen is small but fully stocked and functional. Bathroom is great- water pressure and temperature for the shower are very good. It is located on the fourth floor (no elevator). The apartment is in a quiet complex and I was able to sleep peacefully with the window open (no small feat in Mexico City). The metro is a 5-7 minute walk away, making the rest of the city easily accessible.
I liked the place, but the best part was Nathalie. She is so nice, respectful, and quietly sociable if you're so inclined. I had a lovely time in the apartment with her, chatting when we saw each other, and sharing food sometimes. I also got the sense that for those looking to keep to themselves, Nathalie will give you all the space you want.
A note about the neighborhood: if you are looking to be located in an area where there are tons of cafes, cute restaurants, breweries, and swanky lounges within a 10 minute walk, stay right in the center of Roma Norte, Condesa, Polanco, or Coyoacan. This is not that. But if you are looking to stay somewhere off the beaten tourist track, where regular people live, and with easy access to the rest of the city via metro, this is perfect. You won't bump into many other tourists, and the neighborhood is safe.