{{ form_start(formficheOpportuniteAssainissement) }}
...
</div>
<div class="modal-footer">
    <a href={{ path("app_contact_edit" , { "id": contact.id }) }}>
        <button type="button" class="btn btn-secondary" data-bs-dismiss="modal">Fermer</button>
    </a>
    <button type="button submit" class="btn btn btn-primary">{{ button_label|default('Ajouter') }}</button>
    {{ form_end(formficheOpportuniteAssainissement) }}