Probleme shortcode with list author

I have created a list of my contributors for my website it works well. I'm trying to do this with a shortcode in my functions.php. The list appears well. But when I want to place it in my theme in any page, it appears before the content whereas I want it to be at the bottom of the page of its appropriate page template. I can't seem to find my mistake

    function comite_shortcode( $atts ){
        $contributor_member = array(
             'role'    = 'Contributor',
             'orderby' = 'user_nicename',
             'order'   = 'ASC',
             'number'  = 2,
        );
        $authors = get_users($contributor_member);
            foreach ($authors as $users):
                echo 'div class=column-member';
                    echo 'div class=info-member';
                        echo 'span class=comite-description-name'.$users-display_name.'/span';
                        echo 'span class=comite-description'.$users-institution_rattachementUser.'/span';
                        echo 'span class=comite-description'.$users-fonctionUser.'/span';
                        echo 'span class=comite-description'.$users-responsableUser.'/span';
                    echo'/div';       
                echo'/div';           
                 echo'hr class=separator-member';
            endforeach;
            $html = ob_get_contents();
            return $html; // On renvoie le contenu }
add_shortcode( 'comite', 'comite_shortcode' );