[BUG] git filter-branch failed to suppress a file with an accentuated letter in the filename

git filter-branch --tree-filter has a problem with filename with accentuated letter:

$ git add foo/baré
$ git commit -m "adding a file with an accent"
Created initial commit b27ae97: adding a file with an accent
 0 files changed, 0 insertions(+), 0 deletions(-)
 create mode 100644 "foo/bar\303\251"
$ git filter-branch --tree-filter "rm -rf foo"
Rewrite b27ae977459379e4e7eee1a3d523f908903ea6ae (1/1)
WARNING: Ref 'refs/heads/master' is unchanged

there the foo/baré file still exists, but: $ git filter-branch --tree-filter "rm -rf foo; git add -u" will suppress the said file from history.

The culprit seem to be those line of filter-branch: (around line 279) 
		git diff-index -r $commit | cut -f 2- | tr '\012' '\000' | \
			xargs -0 git update-index --add --replace --remove
git diff-index giving the filename as "foo/bar\303\251"