Is forming a company in Bulgaria enough to save tax?

No. Section 10 of the German Fiscal Code provides that management lies at the centre of senior business direction, that is where the day-to-day decisions of some weight are actually taken. If a Bulgarian company is run from a German desk, management lies in Germany and the company is subject to unlimited German corporate tax liability there, regardless of the Bulgarian registration. Added to that are the controlled foreign company rules in sections 7 to 14 of the Foreign Tax Act, which attribute certain passive income of a controlled foreign company directly to the German shareholder. The structure only holds with premises, staff and decisions on the ground. General information, not tax advice.