{%with messages=get_flashed_messages() %}
{%if messages %}
<p>
  {%for message in messages %}
  {{ message}}
  {%endfor %}
</p>
{%endif %}
{%endwith %}

{%if hasError %}
<p>
  <strong>
    <font color="red">
      {{hasError}}
    </font>
  </strong>
</p>
{%endif%}

<form method="POST" action="{{url_for('after_form')}}">
  <input type="text" name="prenom" placeholder="*Prénom*"/>
  <input type="submit" value="Soumettre"/>
</form>