If any taxpayer fails to make his return, or if the City Finance Officer is dissatisfied as to the correctness of the statements made in the return of any taxpayer, said officer or his authorized agent may enter the premises of such taxpayer at any reasonable time for the purpose of inspecting his books or records of account to ascertain the amount of the tax or to determine the correctness of such statements, as the case may be, and may examine any person under oath administered by said officer or his agent, touching the matters inquired into, or said officer or his authorized agent may fix a time and place for an investigation of the correctness of the return and may issue a subpoena to the taxpayer, or any other person, to attend upon such investigation and there testify, under oath administered by said officer or his agent, in regard to the matters inquired into and may, by subpoena, require him, or any person, to bring with him such books, records and papers as may be necessary.