> good luck in describing to German tax authorities why you have founded it there and not in Germany
Why would you need to explain my business choices to any german authorities? It's none of their business. On top, Estonia is a member of the EU, not some off-shore tax-evasion island.
It was an example. If you are a German citizen you have to explain the tax authorities your business (and I'm pretty sure this is also valid for every or most other EU country)... this includes foreign companies which you own because you need to pay taxes to the country where you live (and it does not matter if your companies are abroad!!!).