The Council shall provide in its ordinances for the punishment of violations of the ordinances of the City. Such punishment may be by a fine not exceeding $500 or by imprisonment of not to exceed 90 days, or both, in the discretion of the court. The Council shall also provide, on regulatory subjects not forbidden by state law, for the imposition of civil penalties in those instances where the person charged with violating an ordinance accepts admission of responsibility for alleged acts. Civil penalties for such violations shall be specified in the respective ordinances and shall be administered by the City Administration or by agents under contract with the City.