Civil Code (Cap. 16), article 323

323. Whosoever has the ownership of the land, has also that of the space above it, and of everything on or over or under the surface; he may make upon his la nd any construction or plantati on, and, under it, any work or excavation, and draw therefrom any products which they may yield, saving, however, the provisions relating to Praedial Easements under Title IV of Part I of Book Second of this Code and any other provision of law in regard to fortifications or other works of defence. Constructions, etc., over or under the land belong to owner.