Index: Python/pythonrun.c
===================================================================
--- Python/pythonrun.c	(révision 84163)
+++ Python/pythonrun.c	(copie de travail)
@@ -134,18 +134,13 @@
     return flag;
 }
 
-#if defined(HAVE_LANGINFO_H) && defined(CODESET)
 static char*
-get_codeset(void)
+get_codec_name(const char *encoding)
 {
-    char* codeset, *name_str;
+    char *name_utf8, *name_str;
     PyObject *codec, *name = NULL;
 
-    codeset = nl_langinfo(CODESET);
-    if (!codeset || codeset[0] == '\0')
-        return NULL;
-
-    codec = _PyCodec_Lookup(codeset);
+    codec = _PyCodec_Lookup(encoding);
     if (!codec)
         goto error;
 
@@ -154,18 +149,28 @@
     if (!name)
         goto error;
 
-    name_str = _PyUnicode_AsString(name);
+    name_utf8 = _PyUnicode_AsString(name);
     if (name == NULL)
         goto error;
-    codeset = strdup(name_str);
+    name_str = strdup(name_utf8);
     Py_DECREF(name);
-    return codeset;
+    return name_str;
 
 error:
     Py_XDECREF(codec);
     Py_XDECREF(name);
     return NULL;
 }
+
+#if defined(HAVE_LANGINFO_H) && defined(CODESET)
+static char*
+get_codeset(void)
+{
+    char* codeset = nl_langinfo(CODESET);
+    if (!codeset || codeset[0] == '\0')
+        return NULL;
+    return get_codec_name(codeset);
+}
 #endif
 
 void
@@ -709,12 +714,17 @@
     char *codeset;
 
     if (Py_FileSystemDefaultEncoding == NULL) {
-        /* On Unix, set the file system encoding according to the
-           user's preference, if the CODESET names a well-known
-           Python codec, and Py_FileSystemDefaultEncoding isn't
-           initialized by other means. Also set the encoding of
-           stdin and stdout if these are terminals.  */
-        codeset = get_codeset();
+        const char *env_encoding = Py_GETENV("PYTHONFSENCODING");
+        if (env_encoding != NULL)
+            codeset = get_codec_name(env_encoding);
+        else {
+            /* On Unix, set the file system encoding according to the
+               user's preference, if the CODESET names a well-known
+               Python codec, and Py_FileSystemDefaultEncoding isn't
+               initialized by other means. Also set the encoding of
+               stdin and stdout if these are terminals.  */
+            codeset = get_codeset();
+        }
         if (codeset != NULL) {
             Py_FileSystemDefaultEncoding = codeset;
             Py_HasFileSystemDefaultEncoding = 0;
Index: Doc/using/cmdline.rst
===================================================================
--- Doc/using/cmdline.rst	(révision 84162)
+++ Doc/using/cmdline.rst	(copie de travail)
@@ -442,6 +442,14 @@
    import of source modules.
 
 
+.. envvar:: PYTHONFSENCODING
+
+   Overrides the encoding used for the filesystem encoding (see
+   :func:`sys.getfilesystemencoding`).
+
+   .. versionadded:: 3.2
+
+
 .. envvar:: PYTHONIOENCODING
 
    Overrides the encoding used for stdin/stdout/stderr, in the syntax
Index: Doc/whatsnew/3.2.rst
===================================================================
--- Doc/whatsnew/3.2.rst	(révision 84162)
+++ Doc/whatsnew/3.2.rst	(copie de travail)
@@ -232,6 +232,15 @@
 
 * Stub
 
+
+Unicode
+=======
+
+The filesystem encoding can be specified by setting the
+:envvar:`PYTHONFSENCODING` environment varible before running the intepreter.
+The value should be a string in the form ``<encoding>``, e.g. ``utf-8``.
+
+
 IDLE
 ====
 
Index: Lib/test/test_pep277.py
===================================================================
--- Lib/test/test_pep277.py	(révision 84162)
+++ Lib/test/test_pep277.py	(copie de travail)
@@ -43,7 +43,7 @@
 
 # Is it Unicode-friendly?
 if not os.path.supports_unicode_filenames:
-    fsencoding = sys.getfilesystemencoding() or sys.getdefaultencoding()
+    fsencoding = sys.getfilesystemencoding()
     try:
         for name in filenames:
             name.encode(fsencoding)
Index: Lib/test/test_sys.py
===================================================================
--- Lib/test/test_sys.py	(révision 84162)
+++ Lib/test/test_sys.py	(copie de travail)
@@ -872,7 +872,13 @@
         fs_encoding = sys.getfilesystemencoding()
         check_fsencoding(fs_encoding)
 
-        # Even in C locale
+        def get_fsencoding(env):
+            output = subprocess.check_output(
+                [sys.executable, "-c",
+                 "import sys; print(sys.getfilesystemencoding())"],
+                env=env)
+            return output.rstrip().decode('ascii')
+
         try:
             sys.executable.encode('ascii')
         except UnicodeEncodeError:
@@ -880,15 +886,22 @@
             # see issue #8611
             pass
         else:
+            # Even in C locale
             env = os.environ.copy()
             env['LANG'] = 'C'
-            output = subprocess.check_output(
-                [sys.executable, "-c",
-                 "import sys; print(sys.getfilesystemencoding())"],
-                env=env)
-            fs_encoding = output.rstrip().decode('ascii')
-            check_fsencoding(fs_encoding)
+            check_fsencoding(get_fsencoding(env))
+            self.assertEqual(fs_encoding, 'ascii')
 
+            # Filesystem encoding is hardcoded on Windows and Mac OS X
+            if sys.platform not in ('win32', 'darwin'):
+                for encoding in ('ascii', 'cp850', 'iso8859-1', 'utf-8'):
+                    env = os.environ.copy()
+                    env['PYTHONFSENCODING'] = encoding
+                    fs_encoding = get_fsencoding(env)
+                    check_fsencoding(fs_encoding, encoding)
+                    self.assertEqual(fs_encoding, encoding)
+
+
     def test_setfilesystemencoding(self):
         old = sys.getfilesystemencoding()
         try: