It is unlawful for any person to construct, install, maintain, or operate a cable television system within any street or public way in the City without first obtaining a franchise under the provisions of this Article II or, if applicable, under the provisions of the Digital Infrastructure and Video Competition Act of 2006; provided, however, that any cable operator authorized to provide cable service under a franchise granted by the City prior to the effective date of this chapter may continue to exercise that authority until the expiration or termination of that franchise.