translation problem

I don't know if load_textdomain in domain-mapping.php work or not but i had to change the function to make it working :

function load_textdomain() {
load_muplugin_textdomain('domainmap', dirname(plugin_basename(__FILE__)).'/languages');
}

and then i can put wp-content/mu-plugins/languages/domainmap-fr_FR.mo

and it works