Civil Code (Cap. 16), article 421

421. Where a wall separates two ten ements, one of which is at a higher level than the other, the owner of the higher tenement s hall bear the whole expense of the construction and repair of the wa ll up to the level of his own tenement: the portion of the wall from that level up to the height specified in article 408 shall be constr ucted and repaired at joint expense. Where neighbour is unwilling to contribute to expense of construction or repair to wall.