Article 669

When the distances in article 670 are not observed, the owner of a wall which is not party wall, adjoining a tenement or piece of land belonging to another, can make in it openings to admit light at the height of the ceiling joints or immediately under the ceiling, and of the size of thirty centimeters square, and, in every case, with an iron grating imbedded in the wall and with a wire screen.

Nevertheless, the owner of the tenement or property adjoining the wall in which the openings are made can close them should he acquire part-ownership thereof, if there be no stipulation to the contrary.

He can also obstruct them by constructing a building on his land or by raising a wall thereon contiguous to that having such openings, unless an easement of light has been acquired. (581a)