I just remembered another - Europa, Europa - the real life story of a Jew who joined the German army. I actually saw it in Germany, in the city were a good part of the film was set. I recall looking around the audience at the 50 or 60 year-olds there (this was 1990) and wondered what they'd...
All of those - White Ribbon and Lives of Others are particularly good.
I'd add Goodbye Lenin
The American Friend (one of my absolute faves)
Marriage of Maria von Braun (indeed, all later Fassbinder are excellent)
and forget the great German silent films
Cabinet of Dr Caligari and, best of all...