The article presents analysis of selected regulations applying to the complaint about finding illegality of the valid judgment introducing into civil proceedings in connection with amendment of the civil code concerning liability of the State Treasury for causing damage of illegality action in exercising public authorities. The Author presents views dominating in the doctrine and judicial decisions defining legal characteristics of the complaint about finding illegality of the valid judgment, its constructive elements, interpretation of the "illegality" definition included in the article 4241 § 1 of the code of civil proceedings. The Author shows also the approximating institutions in domestic order, community institutions.