One attached sign for the purpose of identification and advertising each tenant. The area of the sign shall not exceed an area equivalent to 10% of the total area of the front facade devoted to each tenant or 24 square feet, whichever is larger, as a minimum, but in no event shall any sign exceed 100 square feet. Where the rear of the building or portion of the building occupied has a public entrance from a street or public parking lot, there shall be permitted an additional rear sign not exceeding an area equal to 5% of the front facade, but in any case not exceeding 50 square feet. Where the side of a building or portion of an occupied building abuts a public street, there shall be permitted an additional sign having a total area equal to 5% of the front facade, but shall not exceed 50 square feet. Where any additional use shall occupy the second floor of any premises (exclusive of the first floor), additional front and, where applicable, side and rear signs shall be permitted to be attached to or otherwise painted or represented on the second floor, such additional signs to be separate and apart from ground floor signs and limited in area in the same manner as pertains to the ground floor. No sign shall project above the parapet of the building.