La. Stat. tit. 33 § 4160.27
The governing authority may issue, execute, negotiate, sell, and deliver certificates of the city of Lafayette in an amount up to the total amount of the installments or deferred payments as provided in R.S. 33:4160.26. The certificates shall bear interest at a rate or rates of interest as set forth in the ordinance providing for their issuance, shall be payable annually, and shall mature serially over a period not exceeding twenty years, but in no event shall the certificates extend over a longer period of time than the total period of time for the payment of the local or special assessments described in R.S. 33:4160.26. The certificates may be of such form, bear such date, be of such denomination, and may be subject to such provisions as may be limited or expanded by the provisions of the resolution or ordinance providing for their issuance and as may be most likely to insure the prompt payment and/or marketability. They shall be payable in principal and interest from the irrevocable pledge and dedication of the funds to be derived from the special assessments hereinabove provided which are payable in annual installments or deferred payments as provided for by this Chapter, which funds shall be set aside in a separate trust fund and shall not be drawn upon for any purpose other than to pay the principal and interest of the certificates.
La. R.S. § 33:4160.27