diff --git a/docs/code-style.rst b/docs/code-style.rst
index c8d558f..e54b780 100644
--- a/docs/code-style.rst
+++ b/docs/code-style.rst
@@ -285,7 +285,7 @@
         try {
           statements;
         }
-        catch (Exception& exception) {
+        catch (const Exception& exception) {
           statements;
         }
 
@@ -297,7 +297,7 @@
           {
             statements;
           }
-        catch (Exception& exception)
+        catch (const Exception& exception)
           {
             statements;
           }