Yeah I found it. I want the […] to be at the end of my text, and not on my “Lire la suite” button.
There it is,
function grisaille_new_excerpt_more($more) {
global $post;
return '<br /><a class="more-link" href="'. get_permalink($post->ID) . '">Lire la suite</a>';
}
add_filter('excerpt_more', 'grisaille_new_excerpt_more');