Comme vous l'avez signalé, dans la catégorie du regroupement familial, si le parrain pense que la décision prise est erronée, ou que toutes les circonstances n'ont pas été dûment prises en compte, ou s'il existe des circonstances convaincantes, le parrain a la possibilité d'interjeter appel auprès de la Section d'appel de l'immigration.
As you pointed out, in the case of family class, if the sponsor believes that the decision was made incorrectly, or that all of the circumstances were not appropriately looked at and considered in the context of the decision, or that there are compelling circumstances, the sponsor has the opportunity to take that case to the Immigration Appeal Board and have that decision appealed.