{% load i18n pages_tags mezzanine_tags %}

<div class="col-md-3 col-sm-4 col-xs-6">
    <a class="article-box" href="{{ article.get_absolute_url }}">
        <div class="article-box__header">
            <figure class="article-box__image">
                <img src="//placehold.it/710x475" data-src="//placehold.it/710x475" class="lazyload" />
            </figure>
            <div class="article-box__tags">
                <div class="tag tag--small tag--category">
                    {% trans 'Actualité' %}
                </div>
                <div class="tag tag--small dashed dashed--gray">
                    transmission
                </div>
            </div>
        </div>
        <div class="article-box__content tal">
            <h3 class="article-box__title">{{ article.title }}</h3>
            <div class="article-box__subtitle">
                {{ article.publish_date|date:"DATE_FORMAT" }}
                {% if article.categories %}
                    {% for category in article.categories.all %}
                        | <strong>{{ category }}</strong>
                    {% endfor %}
                {% endif %}
            </div>
            <div class="article-box__desc">
                {{ article.content|richtext_filters|safe }}
            </div>
        </div>
    </a>
</div>

{% load i18n pages_tags mezzanine_tags %}

<div class="col-md-3 col-sm-4 col-xs-6">
    <a class="article-box" href="{{ article.get_absolute_url }}">
        <div class="article-box__header">
            <figure class="article-box__image">
                <img src="//placehold.it/710x475" data-src="//placehold.it/710x475" class="lazyload" />
            </figure>
            <div class="article-box__tags">
                <div class="tag tag--small tag--category">
                    {% trans 'Actualité' %}
                </div>
                <div class="tag tag--small dashed dashed--gray">
                    transmission
                </div>
            </div>
        </div>
        <div class="article-box__content tal">
            <h3 class="article-box__title">{{ article.title }}</h3>
            <div class="article-box__subtitle">
                {{ article.publish_date|date:"DATE_FORMAT" }}
                {% if article.categories %}
                    {% for category in article.categories.all %}
                        | <strong>{{ category }}</strong>
                    {% endfor %}
                {% endif %}
            </div>
            <div class="article-box__desc">
                {{ article.content|richtext_filters|safe|truncatechars:200 }}
            </div>
        </div>
    </a>
</div>

Truncate the article content in article card template
Truncate the article content in article card template
