That would be Fatherland. It's a version of the book, by the same name. That's acually what tipped me off about it. I remember reading the back cover of a book with that scenario. I'm pretty sure that's the movie you're talking about, and really sure that that's the book atleast.
book
http://search.barnesandnoble.com/booksearch/isbnInquiry.asp?userid=Qe5iQ1cCs4&isbn=0061006629&itm=1
movie
http://www.imdb.com/title/tt0109779/