Seller's Failure to Disclose Expropriation: Nullity of Sale and Damages

A lower court annulled a real estate sale based on the seller's failure to disclose a mandatory prior expropriation proceeding that affected the property, leading to the buyer's action for nullity and damages. The appellate court upheld this decision, reasoning that the seller's concealment of the ongoing expropriation constituted a fundamental defect of consent by hiding a burden directly impacting the substance of the thing sold, thus rendering the sale voidable. The highest court partially quashed the judgment, finding that while the lack of disclosure justified annulling the sale, the lower court erred in automatically awarding damages without establishing the extent of the harm suffered by the buyer due to the unilateral breach of the duty to inform regarding a material defect affecting the property's inherent value or use.