diff --git a/doc/Makefile b/doc/Makefile
index 3e8eadec..188929ce 100644
--- a/doc/Makefile
+++ b/doc/Makefile
@@ -1,5 +1,5 @@
 po4a:
-	po4a po4a.conf
+	po4a --localized-charset=ISO-8859-15 po4a.conf
 
 apidocs:
 	epydoc --html -o api --name "LinkChecker source documentation" --url ../index.html ../linkcheck/