diff --git a/reference/info/functions/get-extension-funcs.xml b/reference/info/functions/get-extension-funcs.xml
index cbdb3d80a7..08b2b36d9f 100644
--- a/reference/info/functions/get-extension-funcs.xml
+++ b/reference/info/functions/get-extension-funcs.xml
@@ -1,5 +1,5 @@
 <?xml version="1.0" encoding="iso-8859-1"?>
-<!-- $Revision: 1.6 $ -->
+<!-- $Revision: 1.7 $ -->
 <!-- splitted from ./en/functions/info.xml, last change in rev 1.71 -->
   <refentry id="function.get-extension-funcs">
    <refnamediv>
@@ -18,6 +18,12 @@
      This function returns the names of all the functions defined in
      the module indicated by <parameter>module_name</parameter>.
     </para>
+    <note>
+     <para>
+      The <parameter>module_name</parameter> parameter must be in
+      <emphasis>lowercase</emphasis>.
+     </para>
+    </note>
     <para>
      For example the lines below
      <informalexample>