Usually such German cards use the Visa/Mastercard foreign exchange rate for ATM transactions (no extra fee) and POS transactions (plus currency conversion fee, but no additional fee for using abroad).
In Sweden (and possible in other countries) the ATMs let you choose whether you want to let the ATM (or bank that the ATM belongs to) do the conversion from Euro to Swedish Kronor or your own bank. If you pick the latter option, your bank might charge you for the conversion, I never had the case that the Swedish bank charged for it.
This is known as "dynamic currency conversion" and gives you a much worse deal than letting them charge you in a foreign currency (even when your bank has high fees). The way they do it is by offering a really bad exchange rate. In fact, the Swedish bank charges you for that, it's just hidden in the exchange rate.
Oh really? I never bothered to check the exchange rate. Good to know, I'll let my German bank do the conversion from now on!