When two corporeal movables are united to form a whole, and one of them is an accessory of the other, the whole belongs to the owner of the principal thing.  The owner of the principal thing is bound to reimburse the owner of the accessory its value.  The owner of the accessory may demand that it be separated and returned to him, although the separation may cause some injury to the principal thing, if the accessory is more valuable than the principal and has been used without his knowledge.

Acts 1979, No. 180, §1.