{{ form_start(form, {'attr': {'id': 'newsletter_subscribe'} }) }}

    {% for type, messages in app.session.flashbag.all() %}
        {% for message in messages %}
            <div class="flash-{{ type }}">
                {{ message }}
            </div>
        {% endfor %}
    {% endfor %}

    {{ form_errors(form) }}

    {{ form_row(form.email) }}
    {{ form_widget(form.groups) }}

<input type="submit" value="{{ "S'inscrire"|trans }}" />

{{ form_end(form) }}