The City Council shall have the power to inquire into the official conduct of any department, agency, office, officer or employee of the city. For that purpose, the City Council shall have the power to administer oaths, subpoena witnesses and compel the production of books, papers or other evidence material to the inquiry. The City Council shall provide, by ordinance, penalties for contempt for failing or refusing to obey any such subpoena or to produce any such books, papers or other evidence, and shall have the power to punish any such contempt in the manner provided by the ordinance.