The city taxes provided for by this Chapter shall be assessed and levied on the first day of July in each year, shall become payable on that date, and shall be collected on or before the 10th day of August in each year and on all taxes voluntarily paid before the 10th day of August in each year no collection fee shall be charged, but thereafter a collection fee of four percent (4%) shall be charged and be paid into the general fund of the city. The council may, by ordinance, establish a system for the installment collection of said taxes extending not more than one (1) year and provide for the collection of reasonable interest or collection fees thereon and of penalties for the late payment thereof.