We stayed with Celestin for a night - it was originally meant to be a 4-night stay but unfortunately the apartment had no water due to an electrical issue in the building, so we left after day 1. This was out of Celestin’s control, but we were slightly frustrated not to be have been warned before we arrived.
In any case, Celestin was a warm and welcoming host, the communication was great (other than point mentioned above) and his apartment is great for a short-medium stay in Mexico City.