diff --git a/songbook.py b/songbook.py
index 08cf8e80..3fd2af2e 100755
--- a/songbook.py
+++ b/songbook.py
@@ -36,7 +36,11 @@ def argument_parser(args):
 
 def main():
     # set script locale to match user's
-    locale.setlocale(locale.LC_ALL, '')
+    try:
+        locale.setlocale(locale.LC_ALL, '')
+    except locale.Error as error:
+        # Locale is not installed on user's system, or wrongly configured.
+        sys.stderr.write("Locale error: {}\n".format(error.message))
 
     options = argument_parser(sys.argv[1:])
 
diff --git a/songbook/plastex.py b/songbook/plastex.py
index f1065024..5ba9a55d 100755
--- a/songbook/plastex.py
+++ b/songbook/plastex.py
@@ -80,7 +80,8 @@ def parsetex(filename):
     doc = SongParser.parse(filename)
 
     # /* BEGIN plasTeX patch
-    locale.setlocale(locale.LC_TIME, "%s.%s" % oldlocale)
+    if oldlocale[0] and oldlocale[1]:
+        locale.setlocale(locale.LC_TIME, "%s.%s" % oldlocale)
     # plasTeX patch END */
 
     # Extraction des données