N.Y.C. Admin. Code § 28-118.19: § 28-118.19 Posting of certificates of occupancy.

The owner shall post a copy of the building's certificate of occupancy, partial certificates of occupancy or temporary, including interim, certificates of occupancy in accordance with this section, except buildings occupied entirely by group R-3. Owners of buildings that are not required to have a certificate of occupancy shall post a sign or placard in a form prescribed by the commissioner. The certificate of occupancy or sign, as applicable, shall be permanently affixed to the structure in a conspicuous location in a public hall, corridor, management office of the building or as otherwise prescribed by the commissioner.