In such case, the delinquent shall not be entitled to any commission, and shall forfeit and pay to the county a penalty of twenty percent on the amount found due the county. Such penalty shall be added to the amount so found due, and it shall be the duty of the court in which any action is brought to recover the same, to include such penalty in any judgment which may be rendered against the delinquent in such action. Such penalty, when collected, shall be paid into the county treasury for the benefit of the school fund.