Display list of posts orderby Categories

Hi everyone,

Just like the title says, I’d like to display all my posts from a custom-post-type ordered by categories.

Exemple:

Category 1
Post 1
Post 2
….
Category 2
Post 1
….

For the moment I only display all the posts:

<?php
         $args = array(
               'post_type' => 'fournisseur' ,
               'posts_per_page' => '-1');

         $category_posts = new WP_Query($args);

         if($category_posts->have_posts()) :
            while($category_posts->have_posts()) :
               $category_posts->the_post();
?>
      <h3><?php the_title() ?></h3>
      <div class='post-content'>
         <?php the_content() ?>
      </div>
      <?php
         endwhile;
         else:
      ?>
      <?php
         endif;
      ?>

I’m new to wordpress and php functions so please be nice to me ??

thx.