Merci mille fois ZZUUTT.
C'est parfait.
Voici un lien pour voir ce que cela donne:
http://www.albertpicard.com/?view=categ … egory_id=1
et si cela peut en aider d'autres ... , voici le code de ..templates/frontOffice/default/includes/asides/menu.html
{hook name="category.sidebar-top"}
{ifhook rel="category.sidebar-body"}
{hook name="category.sidebar-body"}
{/ifhook}
{elsehook rel="category.sidebar-body"}
<section id="categories" class="block block-nav" role="navigation" aria-labelledby="categories-label">
<div class="block-heading"></div>
<div class="block-content">
<nav class="nav-categories">
{* define current ID *}
{loop name="current_cat" type="category" current="yes"}
{assign var="current_category_id" value="{$PARENT}"}
{/loop}
{* define the function *}
{function menu level=0}
{if $level == 0}
<ul id="category" class="accordion">
{else}
{if $ID == 1}
<ul id="collapse{$parent}" class="in">
{else}
<ul id="collapse{$parent}" class="collapse">
{/if}
{/if}
{loop name="cat-parent-$level" type="category" parent=$parent need_count_child=1 not_empty="1"}
{if $CHILD_COUNT> 0}
<li><a href="{$URL nofilter}#collapse{$ID}" class="accordion-toggle {if $ID == 1}collapse{else}collapsed{/if}" data-toggle="collapse" data-parent="#collapse{$ID}">{$TITLE}</a>
{menu parent=$ID level=$level+1}
</li>
{else}
<li><a href="{$URL nofilter}">{$TITLE} ({count type="product" category="{$ID}"})</a></li>
{/if}
{/loop}
</ul>
{/function}
{menu parent='0'}
</nav>
</div>
</section>
{/elsehook}
{hook name="category.sidebar-bottom"}