How is capital gains taxed in Portugal?
In the case of real estate income, capital gains in Portugal are always taxed in the country where the property is located, in application of the 1971 tax treaty between France and Portugal to avoid double taxation, and are taxed in Portugal.
Capital gains tax in Portugal is payable at the same time as income tax. So you'll need to declare it on your Portuguese IRS return. All property sales must be declared to the "Autoridad...