mo / po translation files does not seem to work

Check the wp-config.php file and see if your language is defined :

 define('WPLANG', 'your_language');

You could add this if you’re still stuck:

add_action('after_setup_theme','wpse_110727_translate_theme');
function wpse_110727_translate_theme() {
     load_theme_textdomain( 'textdomain', get_template_directory() . '/languages' );
     $locale = get_locale();
     $locale_file = get_template_directory() . "/languages/$locale.php";

         if ( is_readable( $locale_file ) ) require_once( $locale_file );
 }

Just put the translation files into a repertory called /languages/ and upload all files in the root of your theme.

See if it works now. Hope this helps.

EDIT: ‘textdomain’ is the word used in all translation strings :

_e('some content','textdomain');