Here's a quick guide to some of Centro buildings.
Cinelândia or carioca metro stops are good locations for TDM33, RB156, AA37 +++
Tdm is the street name avenida treze de maio, 33 refers to the building number.
RB Avenida Rio branco , AA rua Alvaro Alvim
Next is the room number TDM 33 2414 so that's apartment 2414 which is on floor 24. All elevators don't go to all floor. All elevators have a porter, learn your floor number and say when entering.
TDM & AA are open access. RB 156 you need to register with photo ID, a photo of your passport on your phone is ok. They give you a card which you swipe to get access to the lifts. It's a pita.
AA 37 has a lot of freelance girls working from apartments in this building, it's one of my regular haunts.
So today I tried TDM 33 2414, rang the apartment bell and was let in. I explained I spoke limited Porto and asked if it was ok, just being polite and of course it's ok. They take you to a room and each available girl comes in one at a time, most start blah blah blah, just remember the name of any you like. Only two girls available and I don't like either. I tell the Madame that I will return later, it's not a problem to walk.
I climb down the fire escape stairs to floor 21 apartment 2106. An attractive girl shows me in but she is a bit large for me. Each girl comes in again and I like Julietta. Madame comes in and I tell her my choice is Julietta for 40 minutes. Pay up front 120 (15.70). I take a quick shower (not a pleasant shower room) and back to the room. Julietta is quite nice, small boobs, thin waste, medium ass, nice smiley face. It's a nice session nice, starts with her gyrating her ass into my groin from behind then simulated doggie, while watching in the mirror. Bbbj for 10 minutes with DT me pulling her head in and pushing deep, she is fine with it. I ask for cowgirl for a while then from behind so we can see in the mirror. Eventually ask to leche in the mouth, CIM is pretty standard, no girls have refused. Another quick shower, tip her 20 (£2.60). I ask if she does anal, she smiles and nods, I say next time, she nods again. happy days.
This area is also good for Uruguaiana 24, if you like that type of thing, you will
Here's a list of places currently worth a visit, I cannot take credit for this list as it came mostly from an WA group I'm in.
But places close and open quickly here so you need to research when you get here, but I hope it helps.