Query custom post type only if it contains another custom post type

I finally found a workaround for this, here it goes :

I used “get_user” with a “has_custom_post_type” function to query every user with at least one article written and then added the link to their blog CPT by adding “/blog/display_name” in the href.

Here goes the code

<?php
$blog_url = get_bloginfo('home');
$users_number = 0;
$blogusers = get_users('orderby=registered&order=DESC');
    foreach ($blogusers as $user) {
     $cpt_count = has_custom_post_type( $user->ID, 'article' );
  if (!empty($cpt_count) ) {
    $users_number ++;
    if ($users_number <= 5) {
      echo '<li><a href="' . $blog_url . '/blog/' . $user->user_nicename . '">Le blog de ' . $user->display_name . '</a></li>';
    }
  }
}
?>

Thanks to everyone for your help.