Registration of immovable property and registration of the rights referred to in Article 2521 in the land register are compulsory regardless of the legal status of the owner or holder of the rights.
Without prejudice to the reciprocal rights and actions of the parties for the performance of their agreements, the rights referred to in article 2521 may only be relied on as against third parties if they have been published by means of, as the case may be, registration or entry in the land register in accordance with the provisions of this chapter.