Article 271 of Code of Civil Procedure

The persons concerned shall raise grounds of nullity in the notice provided for in Articles 266 and 268 by a declaration at the Registry of the Court of First Instance at least three days before the hearing scheduled for the sale; otherwise, the right to raise them shall lapse. The sales judge shall rule on the aforementioned grounds of nullity on the day scheduled for the sale before the bidding opens, and his ruling shall not be subject to challenge by any means. If he rules that the notice procedures are void, he shall adjourn the sale to a day he specifies and order those procedures to be repeated. If he rules to dismiss the application for nullity, he shall order the bidding to proceed immediately. The debtor, the possessor, the real security provider and the creditors referred to in Article 2 / 265 shall also raise other grounds of nullity relating to the procedures preceding the sale hearing, as well as grounds of objection to the conditions of sale, at least ten days before the date of that hearing; otherwise, the right to raise them shall lapse. This shall be done by an action brought in accordance with the ordinary procedures before the competent court. The person bringing it must deposit a copy of its statement of claim with the Registry of the Court of First Instance at least three days before the hearing scheduled for the sale. The sales judge ( in his capacity as a judge of urgent matters ( shall, upon the application of the person bringing the aforementioned action, rule to stay the sale or proceed with it according to whether he finds those grounds to be serious or not serious. His ruling shall not be subject to challenge, and if he rules that the sale should proceed, he shall order the bidding to proceed immediately.