diff --git a/babel/messages/extract.py b/babel/messages/extract.py
index 6fad84304..6ebaad8ee 100644
--- a/babel/messages/extract.py
+++ b/babel/messages/extract.py
@@ -710,6 +710,8 @@ def _parse_python_string(value: str, encoding: str, future_flags: int) -> str |
     if isinstance(code, ast.Expression):
         body = code.body
         if isinstance(body, ast.Constant):
+            if isinstance(body.value, bytes):
+                return None  # byte strings are not translatable
             return body.value
         if isinstance(body, ast.JoinedStr):  # f-string
             if all(isinstance(node, ast.Constant) for node in body.values):
diff --git a/tests/messages/test_extract.py b/tests/messages/test_extract.py
index 41eda8903..92b6efaed 100644
--- a/tests/messages/test_extract.py
+++ b/tests/messages/test_extract.py
@@ -180,3 +180,17 @@ def test_issue_1195_2():
         'NOTE: This should still be considered, even if',
         'the text is far away',
     ]
+
+
+def test_extract_byte_string_does_not_crash():
+    """Byte strings like _(b'foo') should be skipped without crashing."""
+    buf = BytesIO(b"""\
+_(b'foo')
+_('hello')
+_(b"bar")
+_('world')
+""")
+    messages = list(extract.extract('python', buf, {'_': None}, [], {}))
+    assert len(messages) == 2
+    assert messages[0][1] == 'hello'
+    assert messages[1][1] == 'world'