Germany has concluded Double Taxation Agreements with most countries around the world (www.bundesfinanzministerium.de ). These Double Taxation Agreements determine which country has the right to levy tax on your income. These are the rules to make sure you are not taxed twice on the same income by providing a system of tax exemptions or tax credits in a cross border context. You can take it that your income will not be taxed twice if these treaties are applied correctly in your case.