diff --git a/aider/commands.py b/aider/commands.py
index a4caf7142..fd4472fbf 100644
--- a/aider/commands.py
+++ b/aider/commands.py
@@ -279,16 +279,17 @@ class Commands:
                 if any(char in word for char in "*?[]"):
                     self.io.tool_error(f"No files to add matching pattern: {word}")
                 else:
-                    if Path(word).exists():
-                        if Path(word).is_file():
-                            matched_files = [word]
+                    fname = Path(self.coder.root) / word
+                    if fname.exists():
+                        if fname.is_file():
+                            matched_files = [str(fname)]
                         else:
                             self.io.tool_error(f"Unable to add: {word}")
                     elif self.io.confirm_ask(
-                        f"No files matched '{word}'. Do you want to create the file?"
+                        f"No files matched '{word}'. Do you want to create {fname}?"
                     ):
-                        (Path(self.coder.root) / word).touch()
-                        matched_files = [word]
+                        fname.touch()
+                        matched_files = [str(fname)]
 
             all_matched_files.update(matched_files)
 
diff --git a/tests/test_commands.py b/tests/test_commands.py
index 70362651d..74a287dd8 100644
--- a/tests/test_commands.py
+++ b/tests/test_commands.py
@@ -276,3 +276,22 @@ class TestCommands(TestCase):
             commit_message = "Test commit message"
             commands.cmd_commit(commit_message)
             self.assertFalse(repo.is_dirty())
+
+    def test_cmd_add_from_sub_dir(self):
+        with GitTemporaryDirectory():
+            io = InputOutput(pretty=False, yes=False)
+            from aider.coders import Coder
+
+            coder = Coder.create(models.GPT35, None, io)
+            commands = Commands(io, coder)
+
+            Path("side_dir").mkdir()
+            os.chdir("side_dir")
+
+            # add a file that is in the side_dir
+            with open("temp.txt", "w"):
+                pass
+
+            # this was blowing up with GitCommandError, per:
+            # https://github.com/paul-gauthier/aider/issues/201
+            commands.cmd_add("temp.txt")