Comment by Chickenosaurus

Yes, the laws don't care about who you bank with. If your "center of life" is in Germany, you are required to pay income taxes. Although "center of life" is not defined in detail in german tax law, there are a number of known indicators that are considered. For example, if you reside in Germany for 183 days per year or more, you are required to pay income tax on all of your income.