No person shall interfere with or obstruct the entrance, during ordinary business hours, of the Commissioner to any house, building, or other premises being used as a place of business which is subject to the provisions of this chapter, while in the discharge of his duties. No person shall interfere with or obstruct the Commissioner in the posting of any placard, in accordance with the requirements of this chapter, in or on any place or premises being used as a place of business subject to the provisions of this chapter, nor shall any person conceal, mutilate, or remove any such placard, except by direction of the Commissioner.