Temporary nonilluminated "For Sale," "For Rent," real estate signs and signs of a similar nature, concerning premises upon which the sign is located: in a residential zoning district (R-1, R-2, R-3, R-MH, R-C), one sign not exceeding six square feet in area per side; in a business, commercial or industrial zoning district (CBD, GC, PC, LI), one sign not to exceed 24 square feet in area, set back at least 10 feet from all property lines. All such signs shall be removed within three days after the sale, lease or rental of the premises or property.