diff --git a/Doc/library/sys.rst b/Doc/library/sys.rst
index cf15d8f..3b9bbb0 100644
--- a/Doc/library/sys.rst
+++ b/Doc/library/sys.rst
@@ -298,15 +298,13 @@
 
 .. function:: getfilesystemencoding()
 
-   Return the name of the encoding used to convert Unicode filenames into system
-   file names, or ``None`` if the system default encoding is used. The result value
-   depends on the operating system:
+   Return the name of the encoding used to convert Unicode filenames into
+   system file names. The result value depends on the operating system:
 
    * On Mac OS X, the encoding is ``'utf-8'``.
 
    * On Unix, the encoding is the user's preference according to the result of
-     nl_langinfo(CODESET), or ``None`` if the ``nl_langinfo(CODESET)``
-     failed.
+     nl_langinfo(CODESET), or ``'utf-8'`` if ``nl_langinfo(CODESET)`` failed.
 
    * On Windows NT+, file names are Unicode natively, so no conversion is
      performed. :func:`getfilesystemencoding` still returns ``'mbcs'``, as
@@ -316,6 +314,10 @@
 
    * On Windows 9x, the encoding is ``'mbcs'``.
 
+   .. versionchanged:: 3.2
+      On Unix, use ``'utf-8'`` instead of ``None`` if ``nl_langinfo(CODESET)``
+      failed. :func:`getfilesystemencoding` result cannot be ``None``.
+
 
 .. function:: getrefcount(object)