La. Revenue and Taxation § 47:535
Nothing contained in this Chapter shall be held to prohibit or prevent the proper enforcement officers of the Division of State Police or authorized representatives of the commissioner from entering upon and exercising the functions of their office or capacity or performing their duties in the enforcement of the provisions of this Chapter, upon any street, road, highway, ferry, bridge or tunnel in this state, whether or not located in whole or in part within the corporate limits of any incorporated municipality of whatsoever size or population. In so doing these officers shall observe and obey the traffic and police regulations of such municipalities and shall, whenever practicably possible, cooperate with the police department of such municipalities, who shall aid and assist them in the enforcement of the provisions of this Chapter and the collection of the taxes due hereunder.
La. Revenue and Taxation § 47:535