N.Y.C. Admin. Code § 28-502.6.2: § 28-502.6.2 Unlawful for outdoor advertising company to sell space on illegal sign.

It shall be unlawful for an outdoor advertising company to sell, lease, market, manage or otherwise make available to others for advertising purposes space on a sign that has been erected, maintained, attached, affixed, painted on or in any other manner represented on a building or premises in violation of any provision of the zoning resolution, this code, the 1968 building code or rules adopted pursuant thereto or to enter into any agreement for such purpose.