I thought that everyone knew. Not only EJ crews, but all pilots operating from a German base have to pay German taxes. The only exception to my knowledge is PTI, they found a very fair deal with the authorities, fighting with the argument that although they are based in Germany, they never fly over it (but over the Atlantic). Still they pay 50% of German taxes (if they do not live there).
For most pilots this problem started already last year I thought...
Dani