The subscription form looks like this, you can access it on that website cocumont.fr/newsletter (of course the address in the form following is the same as the website address and not domain.fr)
<div class="tnp tnp-subscription">
<form method="post" action="https://www.domain.fr/?na=s">
<input type="hidden" name="nlang" value=""><div class="tnp-field tnp-field-email"><label for="tnp-1">Votre adresse email</label>
<input class="tnp-email" type="email" name="ne" id="tnp-1" value="" required></div>
<div class="tnp-field tnp-privacy-field"><label><input type="checkbox" name="ny" required class="tnp-privacy"> <a target="_blank" href="https://www.domain.fr/mentions-legales/" rel="noopener">En continuant, vous acceptez les conditions générales d'utilisation du site</a></label></div><div class="tnp-field tnp-field-button"><input class="tnp-submit" type="submit" value="S'abonner" >
</div>
</form>
</div>