N.Y.C. Admin. Code § 3-101: § 3-101 Flag of the mayor.

The official flag of the mayor shall be the same in design as the official flag of the city. Upon the middle or white bar, however, and above the design of the seal in a semi-circle, there shall be five blue five-pointed stars, typifying the five boroughs of the city. The dimensions of such flag shall be thirty-three inches by forty-four inches.