Section 307. Liens

Every  fine  imposed  by judgment under section three
  hundred four upon an owner shall be a lien upon the premises in relation
  to which the fine is imposed from the time of the filing of a  certified
  copy  of said judgment in the office of the clerk of the county in which
  such premises are situated, subject only to taxes, assessments and water
  rates and to such mortgage and mechanics' liens  as  may  exist  thereon
  prior  to  such  filing; and it shall be the duty of the department upon
  the entry of said judgment to file such certified  copy  forthwith,  and
  such  copy  shall  be  forthwith  indexed  by such clerk in the index of
  mechanics' liens.