diff --git a/reference/filesystem/functions/realpath.xml b/reference/filesystem/functions/realpath.xml
index d5486d4120..4a47df2e0e 100644
--- a/reference/filesystem/functions/realpath.xml
+++ b/reference/filesystem/functions/realpath.xml
@@ -66,6 +66,12 @@
     not normalize the character case.
    </para>
   </note>
+  <note>
+   <para>
+    The function <function>realpath</function> will not work for a file which
+    is inside a Phar as such path would be a virual path, not a real one.
+   </para>
+  </note>
   &fs.file.32bit;
  </refsect1>