Question about visa free (tourist visa) extension in Brazil

This question is surprisingly difficult to answer.

First, as you may already know, the information provided by @Traveller is inaccurate. Decree 9731/2019 explicitly states that visa exempted US citizens may "stay for 90 days, extendable by the same period, as long as it does not exceed 180 days, starting from the date of the first entrance."

But I couldn't find almost any information on the renewal process, or even on whether asking for extension is necessary, since the Decree text doesn't make it clear. None of the 10 Brazilian consulates clarifies this, except this piece of information buried in a PDF on the Miami consulate's website:

GUIDELINES FOR TRAVELING AS TOURIST FROM COUNTRIES EXEMPTED OF VIVIS

(...)

The immigration authorities will stamp your passport with your maximum allowed stay. Otherwise, you are allowed to stay in Brazil for 90 days each time you visit the country. The limit of days you are allowed to stay in a year as a tourist is 180 days (when you sum up all the days spent in Brazil).

If you already know that you need to stay longer than 90 days as a tourist, you must apply for an extension at the nearest Superintendência Regional da Polícia Federal within 30 days of your arrival (more information available at http://www.pf.gov.br/servicos-pf/estrangeiro/prorrogacao-de-prazo-de-estada-deturista-e-viajante-a-negocios-temporario-ii-1).

If you overstay, you are going to be fined and may have problems applying for an extension or for a new visa in the future.

But then, there are still problems with this information:

1. I couldn't find the legal basis for that. Given that no other consulate states the same, it may very well be the case it all came from some random clerk in Miami and it is not correct at all.

2. The Policia Federal link is broken.

There is another form on Policia Federal's site named "Extend stay (visitor)". It's a simple form that, once filled in, will tell you to go to a Policia Federal unit in person. The only problem is that the page leading to that form says it should be used by visa holders only , but this may be reminiscent of the period when there was no such a thing as visa exemption and extension (before 2019).

So, in your shoes, that's what I would do:

1. Fill in the form and take a copy of the receipt.
2. Take a copy of the Miami consulate's PDF.
3. Take a copy of the Decree 9731/2019.
4. Go to Policia Federal.

If this or something else works, make sure to come back and answer your own question. This will definitely be helpful to others.