Thanks !
I toggle “Use theme more link” and leave label “read more” empty, it’s working 🙂
Note :
If it can help someone, “dynamic content > post excerpt” works also for pages (not only post). If an excerpt is filled in the meta, it is automatically displayed in the banner of the page (created in elements). You just have to activate the excerpt for the pages :
function enable_page_excerpt() {
add_post_type_support('page', array('excerpt'));
}
add_action('init', 'enable_page_excerpt');