Go to a Volksbank and have them give you offers from the real estate banks within the association. They offer the conditions mentioned by toxicmolotov.
My contribution from another thread dated 05/17: Today's comparison condition at Volksbanken for example 30 years fixed, 1% repayment, 80% loan-to-value ratio, 2.42% nominal (no special repayment possible)
With a real loan it would be approx. 2.10% nominal
The above conditions were standard conditions, unnegotiated.