The Institut national de la propriété industrielle shall observe and observe itself the principle of contradiction. It may not base its decision on pleas, explanations or documents put forward or produced by the parties without the latter having been given the opportunity to debate them in adversarial proceedings. The parties must expressly state their claims and the factual and legal arguments on which each of their claims is based. All exchanges between the parties and the Institute shall take place in accordance with the procedures laid down by decision of the Director General of the Institut national de la propriété industrielle.