The most important issue for me is always safety and I found this apartment to be quite safe with a 24 hour front door security guard. The apartment is on the first floor and the balcony (with grill) faces a small parking area. And since it does not face the street, there's not a lot of noise, just the usual noise inside the building.
I never met Martin (the security guard,who was quite friendly, showed me into the apartment) but he did help me extend my stay for a week. The AirBnb platform verification system did not work for an extension. So Martin kindly blocked out the week for me while I worked with AirBnb to pay.
The apartment is near the San Jose metro station and it is easy to walk over to San Telmo.
There are a few small problems (1) the shower-head wall attachment was broken so I held the shower-head (2) there is no shower curtain, only a small glass barrier (3) the refrigerator makes a nearly continuous humming sound.
It is much larger than the 35sqm in the description