Board Thread:Questions and Answers/@comment-28015903-20160830173943/@comment-27441457-20160831000151

Hiroyuki Sawano did the soundtrack for AOT, and he's done a LOT of soundtracks with German lyrics even if the series he composes for has nothing to do with Germany (Kill la Kill, Aldnoah Zero, Guilty Crown, Gundam Unicorn, etc.). There are definitely some Germanic elements to AOT, but I highly doubt the walls are located in Germany itself. For one thing, the walled territory is larger than that area of Europe to begin with.

Basically, it doesn't have anything to do with the series. Hiroyuki Sawano just really likes German.