I had a wonderful week long stay at Cecilia's apartment which is nicely situated close to the Metro, Chapultepec Park, with many nice restaurants within walking distance. She is a very kind person who will make you feel at home and is always willing to answer any questions about CDMX that you might have and you make sure your stay is comfortable.
The apartment was very clean, the room was a good size with big sunny windows, a nice comfy bed, a big desk to work from and you also get your own bathroom/shower. I needed strong internet speeds as I work remotely and it was plenty fast enough(50-60 Mbps) to handle my video calls. You also have free rein to use the kitchen/living room/washer/dryer.
I would highly recommend staying at Cecilia's, I actually would have liked to have extended my stay another week but her place is very popular and by the time I went to do so, it was already booked. If I am ever in CDMX again I will definitely try to stay here, thanks Cecilia!