Thanks for sharing this code GuillaumeV - Looks like for the final breadcrumb item the CSS class is missing. Here's the code with this missing piece added:
<div class="BreadCrumb crumb-line lia-breadcrumb lia-component-common-widget-breadcrumb" class="BreadCrumb crumb-line lia-breadcrumb">
<ul id="list" class="lia-list-standard-inline">
<#list page.content.nav.breadcrumb.crumbs as crumb>
<#if crumb_has_next>
<li class="${crumb.wrapperCss}" itemscope itemtype="http://data-vocabulary.org/Breadcrumb">
<a class="lia-link-navigation ${crumb.css}" href="${crumb.url}" itemprop="url"><span itemprop="title">${crumb.text}</span></a>
</li>
<li class="${crumb.separatorCss}">
<span class="separator">${page.content.nav.breadcrumb.seperator}</span>
</li>
<#else>
<li class="${crumb.wrapperCss}" itemscope itemtype="http://data-vocabulary.org/Breadcrumb">
<span class="lia-link-navigation child-thread lia-link-disabled" itemprop="title">${crumb.text}</span>
</li>
</#if>
</#list>
</ul>
</div>
For any developer / Lithium Studio wizard looking to roll this out on their community take a look at the "Using @override to change core components" article to get started.