No retail store shall be located except on the ground floor and it shall have one main entrance opening on a public street, and such place of business shall have no other entrance for use by the public except as hereinafter provided. When a retail store is located on the corner of two streets, such retail store may maintain a door opening on each of the public streets. Provided, however, that any salesroom adjoining the lobby of a hotel or other public building may maintain an additional door into such lobby, so long as same shall be opened to the public. In addition, to the fullest extent consistent with the nature of the establishment, full, free and unobstructed vision shall be afforded from the street and public highway to the interior of the place of sale of dispensing of alcoholic beverages there sold or dispensed. Said building shall be of a permanent type construction and no store shall be located in a mobile home or other movable type building. Said store shall have night lighting all around the outside of the premises, and shall be equipped with a burglar alarm system on the inside of said premises and shall be of a minimum size of 900 square feet. No retail store shall be permitted unless outside the main building but on the premises between the building and the main street adjacent to the premises there is sufficient space on a paved surface for the parking of at least five (5) automobiles, exclusive of parking spaces for employers and employees of the store, except in the Central Business District (B-2) or Planned Business District (PB).