1. Real estate signs not exceeding twelve square feet in area which advertises the sale, rental or lease of the premises upon which such signs are located;

2. Bulletin boards not over twelve square feet in area for public, charitable or religious institutions when the same are located on the premises of such institution;

Signs denoting the architect, engineer or contractor when placed upon work under construction. and not exceeding twelve square feet in area;

4. Professional occupation signs denoting only the name and profession of an occupant in a commercial building, public institutional building or dwelling house, and not exceeding four square feet in area for each occupant therein;

5. Memorial signs or tablets, names of buildings and date of erection when cut into any masonry surface or when constructed of bronze or other incombustible materials;

6. Traffic or other municipal signs, legal notices or railroad crossing signs as may be approved by the city council;

7. Signs of public service companies indicating danger, and aids to service or safety;

8. Signs placed on the interior of a property not intended to be seen by the general public;

9. Gasoline price signs not exceeding twenty square feet per side; provided, however, not more than two separate signs per parcel.