When the buyer has granted a right on the immovable to a third person, rescission may not impair the interest of that person. The seller who receives back the immovable so encumbered is entitled to recover from the buyer any diminution in value suffered by the immovable because of the right of the third person. That recovery may not exceed the supplement the seller would have recovered if the buyer had not encumbered the immovable and had decided to keep it.
La. C.C. § 2596