N.Y. Second Class Cities Law § 204

§ 204. Certification and approval of contracts and conveyances. No\nwritten contract providing for the payment of two hundred dollars or\nmore, entered into by the city or any of its officers, boards or\ndepartments, shall become effective or be acted under until there shall\nbe indorsed thereon by the corporation counsel or an assistant, a\ncertificate to the effect that the city officer, board or department\nwhich has executed the same on behalf of the city, had authority and\npower to make such contract, and that such contract is in proper form\nand properly executed; he shall approve all deeds, conveyances, leases\nand abstracts of title affecting property acquired, conveyed to or\nleased by the city; and he shall attend to all the law business of the\ncity and discharge such other duties as may be prescribed by law or\nordinance of the common council.\n