diff --git a/breezy/bzr/inventorytree.py b/breezy/bzr/inventorytree.py
index 79ec5fe276..54083daf5c 100644
--- a/breezy/bzr/inventorytree.py
+++ b/breezy/bzr/inventorytree.py
@@ -671,7 +671,16 @@ def add(self, file_list, recurse=True):
                 if this_ie.kind != 'directory':
                     this_ie = self._convert_to_directory(this_ie, inv_path)
 
+                abspath = abspath.encode(osutils._fs_enc)
+
                 for subf in sorted(os.listdir(abspath)):
+                    try:
+                        subf = subf.decode(osutils._fs_enc)
+                    except UnicodeDecodeError:
+                        relpath = (directory.encode(osutils._fs_enc) +
+                                   b'/' + subf)
+                        raise errors.BadFilenameEncoding(relpath,
+                                                         osutils._fs_enc)
                     inv_f, _ = osutils.normalized_filename(subf)
                     # here we could use TreeDirectory rather than
                     # string concatenation.
diff --git a/breezy/bzr/workingtree.py b/breezy/bzr/workingtree.py
index 91149ddf84..d4cc82c5f9 100644
--- a/breezy/bzr/workingtree.py
+++ b/breezy/bzr/workingtree.py
@@ -1104,7 +1104,15 @@ def list_files(self, include_root=False, from_dir=None, recursive=True):
 
                     # But do this child first if recursing down
                     if recursive:
-                        new_children = sorted(os.listdir(fap))
+                        new_children = []
+                        for subf in os.listdir(fap.encode(osutils._fs_enc)):
+                            try:
+                                new_children.append(subf.decode(osutils._fs_enc))
+                            except UnicodeDecodeError:
+                                relpath = fp.lstrip('/').encode(osutils._fs_enc) + b'/' + subf
+                                raise errors.BadFilenameEncoding(relpath,
+                                                                 osutils._fs_enc)
+                        new_children.sort()
                         new_children = collections.deque(new_children)
                         stack.append((f_ie.file_id, fp, fap, new_children))
                         # Break out of inner loop,
diff --git a/breezy/git/workingtree.py b/breezy/git/workingtree.py
index a87b6c0295..784a190858 100644
--- a/breezy/git/workingtree.py
+++ b/breezy/git/workingtree.py
@@ -482,7 +482,13 @@ def call_action(filepath, kind):
                     trace.warning('skipping nested tree %r', abs_user_dir)
                     continue
 
-                for name in os.listdir(abs_user_dir):
+                for name in os.listdir(abs_user_dir.encode(osutils._fs_enc)):
+                    try:
+                        name = name.decode(osutils._fs_enc)
+                    except UnicodeDecodeError:
+                        relpath = user_dir.encode(osutils._fs_enc) + b'/' + name
+                        raise errors.BadFilenameEncoding(relpath,
+                                                         osutils._fs_enc)
                     subp = os.path.join(user_dir, name)
                     if self.is_control_filename(subp) or self.mapping.is_special_file(subp):
                         continue
diff --git a/breezy/tests/per_workingtree/test_smart_add.py b/breezy/tests/per_workingtree/test_smart_add.py
index 709f0670f4..e458c4389b 100644
--- a/breezy/tests/per_workingtree/test_smart_add.py
+++ b/breezy/tests/per_workingtree/test_smart_add.py
@@ -377,3 +377,28 @@ def test_inaccessible_implicit(self):
         #       just ignore files that don't fit the normalization
         #       rules, rather than exploding
         self.assertRaises(errors.InvalidNormalization, self.wt.smart_add, [])
+
+
+class TestIllegalPaths(per_workingtree.TestCaseWithWorkingTree):
+
+    def test_bad_fs_path(self):
+        if osutils.normalizes_filenames():
+            # You *can't* create an illegal filename on OSX.
+            raise tests.TestNotApplicable('OSX normalizes filenames')
+        self.requireFeature(features.UTF8Filesystem)
+        # We require a UTF8 filesystem, because otherwise we would need to get
+        # tricky to figure out how to create an illegal filename.
+        # \xb5 is an illegal path because it should be \xc2\xb5 for UTF-8
+        tree = self.make_branch_and_tree('tree')
+        self.build_tree(['tree/subdir/', 'tree/subdir/somefile'])
+        tree.add(['subdir', 'subdir/somefile'])
+
+        with open(b'tree/subdir/m\xb5', 'wb') as f:
+            f.write(b'trivial\n')
+
+        with tree.lock_tree_write():
+            e = self.assertListRaises(errors.BadFilenameEncoding,
+                                      tree.smart_add, ['tree'])
+        # We should display the relative path
+        self.assertEqual(b'subdir/m\xb5', e.filename)
+        self.assertEqual(osutils._fs_enc, e.fs_encoding)
diff --git a/doc/en/release-notes/brz-3.0.txt b/doc/en/release-notes/brz-3.0.txt
index 6f70d94026..329d9caf3d 100644
--- a/doc/en/release-notes/brz-3.0.txt
+++ b/doc/en/release-notes/brz-3.0.txt
@@ -171,6 +171,11 @@ Bug Fixes
 
 * Support '0' markers in fastimport plugin. (Jelmer Vernooij, #1744615)
 
+* Raise a clearer exception when encountering filenames not in
+  the current encoding when running 'brz add'.
+  (Jelmer Vernooij, #715547)
+
+
 Documentation
 *************