Signs stating that the carrying of firearms is prohibited on any private property shall be clearly and conspicuously posted at any entrance, open to the public, of a building, premises, or real property.
A sign shall be considered conspicuous if it is at least eight (8) inches by ten (10) inches in size and contains writing in contrasting ink using not less than thirty-six (36) point type.
D.C. Mun. Regs. tit. 24, r. 24-2346