596. The debtor may by opposition demand the nullity in whole or in part of a seizure in execution:(1) on the ground of an irregularity in the seizure, which causes him a serious prejudice, saving the power of the court to authorize the seizing creditor to remedy the irregularity, if possible;
(2) on the ground of the property being exempt from seizure;
(3) on the ground of the extinction of the debt;
(4) on any other ground of a nature to affect the judgment sought to be executed.