Me. Rev. Stat. tit. 23, § 1922

This chapter shall not supersede the provisions of any other statute, regulation, ordinance or resolution, the requirements of which are more strict than those of this chapter and not inconsistent therewith, whether such ordinance, bylaw, regulation, resolution or statute was enacted before or after the effective date of this chapter. It shall not be inconsistent with this chapter if such statute, regulation, ordinance or resolution prohibits official business directional signs.