In the sale of immovable property, even though it may have been stipulated that upon failure to pay the price at the time agreed upon the rescission of the contract shall of right take place, the vendee may pay, even after the expiration of the period, as long as no demand for rescission of the contract has been made upon him either judicially or by a notarial act. After the demand, the court may not grant him a new term. (1504a)