Section 1129. Members of police department; no other office

Any police
  commissioner or any member of the police  force  who  shall  accept  any
  additional  place  of public trust or civil emolument except as a member
  of a community board, or who shall during his or her term of  office  be
  nominated  for any office elective by the people, except a member of the
  police force appointed, nominated or elected to  a  board  of  education
  outside  of  the  city  of  New  York,  and  shall  not, within ten days
  succeeding same, decline the said nomination, shall be deemed thereby to
  have resigned his or her commission and  to  have  vacated  his  or  her
  office,  and  all  votes cast at any election for any person holding the
  office of police commissioner, or within thirty days  after  he  or  she
  shall have resigned such office, shall be void.
    The  foregoing  provisions shall not apply to any member of the police
  force who, with the written authorization of the mayor, shall accept any
  additional place of public trust or civil emolument while  on  leave  of
  absence without pay from the department.