The amount of any tax, penalty and filing and processing fee imposed under this chapter shall be deemed to be a debt to the city. Any person carrying on any business without first having procured a license from said city to do so shall be liable to the city for an amount equal to the amount of such tax, penalty and filing and processing fee, if any, together with all appropriate costs of collection, including reasonable attorney fees, if litigation is reasonably required to collect the same.
(`83 Code, § 5.04.110)