diff --git a/lemonldap-ng-handler/lib/Lemonldap/NG/Handler/ApacheMP2/Main.pm b/lemonldap-ng-handler/lib/Lemonldap/NG/Handler/ApacheMP2/Main.pm
index 2e9a3741c..25125fc96 100644
--- a/lemonldap-ng-handler/lib/Lemonldap/NG/Handler/ApacheMP2/Main.pm
+++ b/lemonldap-ng-handler/lib/Lemonldap/NG/Handler/ApacheMP2/Main.pm
@@ -96,6 +96,7 @@ sub set_custom {
 sub set_header_in {
     my ( $class, $request, %headers ) = @_;
     while ( my ( $h, $v ) = each %headers ) {
+        utf8::downgrade($v);
         $request->env->{'psgi.r'}->headers_in->set( $h => $v );
     }
 }