Whenever I try to get a file with a non-English character, git annex gives me trouble that I don't have with English filenames from the same repo. I'm hesitant to file a bug report here since the problem seems to stem from rsync not being able to handle the characters. Here's the output (everything enclosed in pointy brackets are redacted):

get <artist>/<album>/<track> (from origin...) 
git-annex: /home/<username>/Music/.git/annex/transfer/upload/53e11324-041f-11e2-93ca-27250d76416f/SHA256-s7941079--c5a31f15302d57563d8cd35e43ba34669b5485a99b617a83c89fba02fb2ca981: commitBuffer: invalid argument (invalid character)
protocol version mismatch -- is your shell clean?
(see the rsync man page for an explanation)
rsync error: protocol incompatibility (code 2) at compat.c(174) [Receiver=3.0.9]

git-annex-shell: sendkey: 1 failed
  rsync failed -- run git annex again to resume file transfer

  Unable to access these remotes: origin

  Try making some of these repositories available:
        604f093f-a980-4740-a9df-d21b580a2ba4 -- origin (<remote>)
failed

It spits out similar errors for all files with Japanese/German/French/special characters, and ends with this on the last line:

git-annex: get: 138 failed