diff --git a/release.sh b/release.sh
index 29dfade6..1017b8a0 100755
--- a/release.sh
+++ b/release.sh
@@ -20,6 +20,7 @@ fi
 
 VERSION=$1
 
+export LANG=C
 mv ChangeLog ChangeLog.old
 echo -e "Weboob $VERSION (`date +%Y-%m-%d`)\n\t \n\n" > ChangeLog
 cat ChangeLog.old >> ChangeLog
diff --git a/tools/make_man.sh b/tools/make_man.sh
index daf03cab..ad49ee73 100755
--- a/tools/make_man.sh
+++ b/tools/make_man.sh
@@ -3,6 +3,9 @@
 # stop on failure
 set -e
 
+# Use C local to avoid local dates in headers
+export LANG=C
+
 [ -z "${TMPDIR}" ] && TMPDIR="/tmp"
 
 # do not allow undefined variables anymore