The Council, the City Manager or any person or committee authorized by either or both of them shall have power to inquire into the conduct of any department or office of the city; to make investigations as to city affairs, and for that purpose may subpoena witnesses, request the administration of oaths by the City Secretary for purposes necessary in regards to this section, and compel the production of books, papers and other evidence material to said inquiry. The Council may provide by ordinance penalties for contempt in refusing to obey any such subpoenas or failure to produce books, papers and other evidence, and shall have the power to punish any such contempt in the manner provided by ordinance.