The heads of all administrations and departments, except the police and law departments, and the chiefs of each and every division or bureau thereof, and all borough presidents shall, with reasonable promptness, furnish to any taxpayer desiring the same, a true and certified copy of any book, account or paper kept by such administration, department, bureau or office, or such part thereof as may be demanded, upon payment in advance of ten cents for every hundred words thereof by the person demanding the same. The provisions of this section shall not apply to any papers prepared by or for the comptroller for use in any proceeding to adjust or pay a claim against the city or any agency, or by or for counsel for use in actions or proceedings to which the city or any agency is a party, or for use in any investigation authorized by this charter.