A final judgment rendered in any civil proceeding brought by the state for violation of this article to the effect that a defendant has violated said article shall be prima facie evidence against such defendant in any proceeding brought by any other party against such defendant pursuant to section eight of this article, as to all matters with respect to which said judgment or decree would be an estoppel as between the parties thereto: Provided, That this section shall not apply to consent judgments or decrees entered before any testimony has been taken.