No signs required. Emphasis mine.§95.5. Possession of firearm on premises of alcoholic beverage outlet
A. No person shall intentionally possess a firearm while on the premises of an alcoholic beverage outlet.
B. "Alcoholic beverage outlet" as used herein means any commercial establishment in which alcoholic beverages of either high or low alcoholic content are sold in individual servings for consumption on the premises, whether or not such sales are a primary or incidental purpose of the business of the establishment.
C. The provisions of this Section shall not apply to the owner or lessee of an alcoholic beverage outlet, or to an employee of such owner or lessee, or to a law enforcement officer or other person vested with law enforcement authority acting in the performance of his official duties.
D. Whoever violates the provisions of this Section shall be fined not more than five hundred dollars or imprisoned for not more than six months, or both.
From the Lousiana Boardwalk Code of Conduct (posted publicly at the Boardwalk):
12. No firearms or other weapons are allowed, regardless of whether bearer holds a concealed weapons permit; law enforcement officers while on duty are excluded.
That IS on a sign, posted at the Boardwalk, and any sign will do in Louisiana. Ghostbuster, hidden, hard to see, in French, doesn't matter. Any "no guns" sign has the force of law.