Actually Greece has in a way already paid for a bailout of DB (+ other German & French banks). Just before the (famous?) PSI[1], the Greek state (through retirement funds, universities & other public and semi-public institutions) bought off a lot of (Greek) government bonds from these banks. Then the haircut happened. So instead for these banks to suffer the losses, they were moved to the taxpayer.
[1] https://en.wikipedia.org/wiki/Private_sector_involvement