Idaho Code § 67-4608
Except as provided in section 67-4607 d., Idaho Code, after the designation of a historic district, no exterior portion of any building or other structure (including walls, fences, light fixtures, steps and pavement, or other appurtenant features) nor aboveground utility structure nor any type of outdoor advertising sign shall be erected, altered, restored, moved or demolished within such district until after an application for a certificate of appropriateness as to exterior features has been submitted to and approved by the historic preservation commission. The county or city shall require such a certificate to be issued by the commission prior to the issuance of a building permit or other permit granted for purposes of constructing or altering structures. A certificate of appropriateness shall be required whether or not a building permit is required. For purposes of this chapter, "exterior features" shall include the architectural style, general design and general arrangement of the exterior of a building or other structure, including the color, the kind and texture of the building material and type and style of all windows, doors, light fixtures, signs, other appurtenant fixtures and natural features such as trees and shrubbery. In the case of outdoor advertising signs, "exterior features" shall be construed to mean the style, material, size and location of all such signs. The commission shall not consider interior arrangement and shall take no action under this section except for the purpose of preventing the construction, reconstruction, alteration, restoration, moving or demolition of buildings, structures, appurtenant fixtures, outdoor advertising signs or natural features in the historic district which would be incongruous with the historical, architectural, archeological or cultural aspects of the district.
Idaho Code § 67-4608