Some would say that B&N is going to have an uphill battle in front of them. According to the latest figures from Bowker, Amazon has a 43% share of the German ebook market, with Apple coming in second at 10%. Figures from a University of Hamburg poll back in October suggests that Amazon and Apple have 57% and 27%, respectively, which would make B&N's position even worse.
But I'm not so sure. Germany has allowed publishers to control the price of books since long before the idea popped in the heads of the Price Fix 6 here in the US. That means that B&N won't have to compete on price - just support, hardware, and marketing. Which means that if B&N finds a local chain to partner with, they will be in a position to offer a hands on expereince that the other 2 do not. Amazon doesn't have a store presence in Germany. While Apple does have 8 stores there, I've always gotten the feeling that Apple was far more interested on selling hardware, not content.
And we already know that B&N is probably going to work with local partners (instead of opening their own ebookstore). There are several possible partners in the German market already, and at least 2 (Weltbild and Thalia) are heavily committed to ebooks. Either one could make a decent partner.