A buyer threatened with eviction must give timely notice of the threat to the seller. If a suit for eviction has been brought against the buyer, his calling in the seller to defend that suit amounts to such notice.
A buyer who elects to bring suit against a third person who disturbs his peaceful possession of the thing sold must give timely notice of that suit to the seller.
In either case, a buyer who fails to give such notice, or who fails to give it in time for the seller to defend himself, forfeits the warranty against eviction if the seller can show that, had he been notified in time, he would have been able to prove that the third person who sued the buyer had no right.
La. C.C. § 2517