If you ever build anything touching German real estate, you will meet Grunderwerbsteuer. It's the property transfer tax, it's set per state, and the rates are not close to each other. Bavaria and Saxony sit at 3.5%. NRW, Brandenburg, Saarland, Schleswig-Holstein and Thuringia sit at 6.5%. The rest land somewhere in between.

On a 400,000 euro...