Civil Code (Cap. 16), article 696

696. (1) Where the thing forming the subject of a legacy belongs to a person other than t he testator, such legacy shall be null, unless it is stated in the will that the testator knew th at the thing was not his property, but the property of others, in whic h case the heir may elect e ither to acquire the thing bequeathed in or der to make delivery thereof to the leg atee, or to pay to such legatee the fair value thereof. 184 [CAP. 16. CIVIL CODE (2) Where, however, the thing so bequeathed, although belonging to others at the time of the will, is the property of the testator at the time of his d eath, the legacy shall be valid. Legacy of thing belonging to heir or legatee.