I still have clients in Germany. Can I move anyway?

Having clients in Germany does no harm as long as the work does not take place there. What decides is where the work is performed and directed, not where the invoice goes. Anyone working from Bulgaria and taking the decisions there has their place of management in Bulgaria under section 10 of the Fiscal Code. Anyone who instead keeps an office, staff or fixed premises in Germany may create a taxable connection there and remains liable in Germany for the corresponding income under section 1(4) of the Income Tax Act. This point belongs on the tax adviser's desk before the changeover. General information, not tax advice.