Brazil used to strip citizenship for naturalising elsewhere, with narrow exceptions. A 2023 constitutional amendment reversed that — and a fair amount of content online still describes the old rule.
Constitutional Amendment (EC) 131/2023 removed automatic loss of Brazilian nationality for simply acquiring another citizenship. Under the current rule, a Brazilian loses their nationality only if a court cancels it for fraud or an attack on the democratic order, or if the person files an express, voluntary request to give it up — and even that’s barred if it would leave them stateless. A Brazilian who naturalises in Germany today keeps both citizenships automatically, with no action required on either side.
The old rule wasn’t theoretical — a 2018 Supreme Court case involving a Brazilian who’d naturalised as American found she’d lost her Brazilian nationality under the pre-2023 regime, causing real anxiety in Brazil’s emigrant community at the time. If you’re reading older material describing citizenship loss on naturalisation, it’s describing a rule that no longer applies.