Seller's Undisclosed Mortgage Breach Justifying Contract Rescission

The case involves a dispute arising from a contract for the sale of a building, where the buyer sought rescission after discovering a pre-existing, significant mortgage that had not been disclosed by the seller, despite the contract mentioning "no rights" on the property. The Court of Cassation quashed the lower court's decision, reasoning that the seller's explicit guarantee against any encumbrances constituted a fundamental obligation, and the existence of the undisclosed mortgage, even if subject to a potential future discharge, constituted a breach of this essential contractual guarantee, justifying the buyer's request for rescission of the sale.