Codeigniter allow accented letters in URL

So you have this preference in CodeIgniter:

$config['permitted_uri_chars'] = 'a-z 0-9~%.:_\-';

How do you change this so that é, à, è, ç etc. are allowed? I need this for my开发者_Go百科 search url's.

Add any characters you want to use in your permitted_uri_chars list.

$config['permitted_uri_chars'] = 'a-z 0-9~%.:_\-éàèç';