diff --git a/tests/test_indent_simple.py b/tests/test_indent_simple.py
index bf35854..2150ce0 100644
--- a/tests/test_indent_simple.py
+++ b/tests/test_indent_simple.py
@@ -226,6 +226,42 @@ def test_environment_c(self):
         ret = texplain.indent(text)
         self.assertEqual(ret.strip(), formatted.strip())
 
+    def test_environment_star_a(self):
+        text = r"""
+\begin{figure*}[b]
+    \centering
+    \includegraphics[width=\linewidth]{example-image}
+\end{figure*}
+        """
+
+        formatted = r"""
+\begin{figure*}[b]
+    \centering
+    \includegraphics[width=\linewidth]{example-image}
+\end{figure*}
+        """
+
+        ret = texplain.indent(text)
+        self.assertEqual(ret.strip(), formatted.strip())
+
+    def test_environment_star_b(self):
+        text = r"""
+\begin{figure*}[b]
+\centering
+\includegraphics[width=\linewidth]{example-image}
+\end{figure*}
+        """
+
+        formatted = r"""
+\begin{figure*}[b]
+    \centering
+    \includegraphics[width=\linewidth]{example-image}
+\end{figure*}
+        """
+
+        ret = texplain.indent(text)
+        self.assertEqual(ret.strip(), formatted.strip())
+
     def test_environment_nested_a(self):
         text = r"""
 Some text \begin{equation} \begin{split} a = b \end{split} \end{equation} some more text.
diff --git a/texplain/__init__.py b/texplain/__init__.py
index 93a4e72..5a19527 100644
--- a/texplain/__init__.py
+++ b/texplain/__init__.py
@@ -1593,8 +1593,8 @@ def indent(
             elif env == "document":
                 continue
             else:
-                opening = r"\\begin{" + env + r"}"
-                closing = r"\\end{" + env + r"}"
+                opening = r"\\begin{" + re.escape(env) + r"}"
+                closing = r"\\end{" + re.escape(env) + r"}"
             indices = find_matching(
                 text,
                 opening,