Apparently it has just been formally ruled that a condo corporation can restrict unit owners from renting their property on Airbnb, etc.

Parenthetically, this same rule was recently incorporated into my building’s bylaws; it is not a new trend.

My sense of this for Brazil is that it is up to each building to decide whether to invoke the restriction; meaning, pistols at dawn following condo syndicate’s meetings and voting process.

Word to the wise aspect: check that your host can confirm he\she is being transparent about the status of their building while not banking on their guest(s) flying under the radar. Be aware of the laws at the time you book ... the Airbnb site is usually up to date on the rules by country. 

Bear in mind that these rulings can jump back and forth. About 18 months ago for the same case it was ruled that such rentals were not prohibited because they did not constitute commercial activity. 

Does it mean advertising on a rental  platform in a case where the building involved upholds the restriction is prohibited? I do not know. I would think it is the actual physical follow-through of taking a guest that is disallowed. In that case, one might inadvertently walk into a hassle. 

This is an interesting question. Does a condo board have inherent authority to prohibit owners from renting out their units on Airbnb? I suspect that the bylaws would have to be amended to grant the board that power. This question is bound to end up before a court, if it hasn't already.

I guess the answer will depend on Brazilian laws. But these may be overridden by whatever regulations govern the particular building and which the owner has signed up to observe. These regulations can be very restrictive. (For example, I live in a building that prohibits any letting unless it is for at least 12 months and where the renters have to be interviewed and approved in advance.)

I feel the caution by @Riobard is timely. I can’t imagine any ‘renter’ arriving from overseas is going to want to find themselves unwelcome and likely to be thrown out on the street suddenly.