La. Stat. tit. 53 § 205
Any person, the state, or any political subdivision engaged in or preparing to engage in, the manufacture, transportation or storage of any product to be used in the preparation of the United States or of any of the states for defense or for war or in the prosecution of war by the United States or the manufacture, transportation, distribution, or storage of gas, oil, coal, electricity, or water, or the operation of any public utility, whose property, except where it fronts on water or where there are entrances for railway cars, vehicles, persons or things, is surrounded by a fence or wall, or a fence or wall and buildings, may post around his or its property at each gate, entrance, dock or railway entrance and every one hundred feet of waterfront a sign reading "No Entry Without Permission".
Whoever wilfully enters upon premises so posted without permission of the owner shall be fined not less than five dollars nor more than fifty dollars or imprisoned for not less than two days nor more than ten days, or both.
This Section and R.S. 53:206 shall be in effect only so long as a state of war exists between the United States and any other nation. Any violation of this Section committed while it is in force may be prosecuted and punished thereafter, whether or not this Section is in force at the time of the prosecution or punishment.
La. R.S. § 53:205