Ajax callback returns value but wrapper isn't filled
Edit your code into the code below:

 $form['show_liste_produits'] = array(
     '#type' =&gt; 'submit',   
     '#value' =&gt; t('Lister les produits'),   
     '#ajax' =&gt; array(
         'callback' =&gt; 'stockerAll',
         'wrapper' =&gt; 'listeProduits',      
     ),
);

$form['listeProduits'] = array(
    '#type' =&gt; 'container',
    '#attributes' =&gt; array('id'=&gt; 'listeProduits'),         
);


If it doesnt work,make sure first if stockerAll is called. Insert watchdog('test','test'); in the stockerAll function . After doing so, run the program, check your drupal database, particularly the watchdog table and check whether 'test' is in the latest log.

function stockerAll($form, $form_state){
    watchdog('test','test');
    return 'test';
}


If stockerAll is called, clear cache of the browser to make sure the updated code is the one executing. Else, there's something wrong with the way you invoke your function.