7. a. The person having control of an indoor public place or workplace shall place in every public entrance to the indoor public place or workplace a sign, which shall be located so as to be clearly visible to the public and shall contain letters or a symbol which contrast in color with the sign, indicating that smoking is prohibited therein, except in such designated areas as provided pursuant to this act. The sign shall also indicate that violators are subject to a fine. The person having control of the indoor public place or workplace shall post a sign stating "Smoking Permitted" in letters at least one inch in height or marked by the international symbol for "Smoking Permitted" in those areas where smoking is permitted.
b. The provisions of this section shall not be construed to prevent a lessee of the workplace, or space within the building or indoor public place, from enforcing the smoking restrictions imposed by the owner or operator of a commercial or other office building or other indoor public place.