In all cases of the sale of school lands known as sixteenth sections, where the purchase money has not been paid, the purchaser may annul the sale, upon application to the district court of the parish where the land is situated subject to the following conditions: (1) that the judgment of nullity shall be obtained at the cost of the applicant and contradictorily with the district attorney and the school board of the district; (2) that it shall appear upon the trial thereof that the value of the land has not been impaired by any act of the purchaser.  The purchaser shall not be entitled to the repayment of any part of the purchase money paid at the time of his purchase.