{% if comments_form.error %}
{{ comments_form.error|e }}
{% endif %}

Note: you can also suggest changes to the official documentation text.

Name:
E-Mail Address:
Comment Title:
{% if preview %}

Preview

{{ preview.title|e or ' ' }}

{{ preview.parsed_comment_body or ' ' }}
by {{ preview.author|e }}, written on {{ preview.pub_date|datetimeformat }} | #
{% endif %}