Seeing as how people are offering some alternative locations, how about Cologne (Koln). Just a little further east with a very nice airfield at Leverkusen (EDKL) which is approx 15km from Cologne.
The city offers some interesting sights and also boasts seven separate christmas markets with the most spectacular set around the main cathederal. The 'alter markt' is very olde worlde and is worth a visit also.