As a resident of Germany, you are subject to German Tax law. Check the U.S. /German Tax Treaty. Your U.S. Social Security is subject to German taxation only and is entered on German the tax form where any German Social Security is entered. Convert your U.S. Social Security to Euros and add it to any German Social Security. If you are reporting a private German Pension on a U.S. 1040, enter it as Miscellaneous Income and file appropriate form to claim a foreign tax credit for any tax on the pension paid to Germany.
