My customer just told me that they "will have to pay 24% of taxes on [my] invoices to the Brazilian government".
Unfortunately, I don't have an authoritative source. But common sense tells me that he is right. For example, some years ago, I imported a product from Switzerland, and when I picked it up at the customs office I had to pay VAT. Note that while Switzerland is in Europe, it is not part of the European Union (EU).
I guess in many countries there are similar rules, also concerning the import of services. Only, in Germany, many (not all) businesses and freelancers can get their expenses for VAT back in yearly or shorter intervals. I don't know how it is in Brazil.