Originally Posted by
NWA747SNN
I can show either passport. I do not need a visa to enter Germany as a US citizen, but the EU passport will save time.
I know that you don't need a visa.
Each country / immigration zone (like schengen states within EU) requires that you show the passport that belongs to this country / immigration zone.
When you get to Germany, you need to show the European passport (if it is a EU passport) and you will have to show the American one, once you return.