Advertising signs, when the same are attached to a building and advertise only services, articles or products which are offered within the building to which such sign is attached, and provided that such signs shall not extend above the outside walls of such building, nor more than one (1) foot from the face of the walls of such building, nor shall it contain an area of more than twelve (12) square feet. One freestanding sign not to exceed twenty-four (24) feet in height will be allowed in the front yard provided such sign does not exceed thirty (30) square feet in area.