The seizure of a patent shall be effected by an extrajudicial document served on the owner of the patent, on the Institut national de la propriété industrielle and on persons having rights in the patent; it shall render unenforceable against the seizing creditor any subsequent modification of the rights attached to the patent.
On pain of nullity of the seizure, the seizing creditor must, within the prescribed period, appeal to the court for the validity of the seizure and for the purpose of putting the patent up for sale.