La. R.S. 33:3557

The amounts assessed in the ordinance or resolution shall be due and exigible immediately upon its passage and, if the amounts are not paid within thirty days after the passage of the ordinance or resolution, the municipality, or its transferees, may proceed by suit against the assessed properties and the owners thereof to enforce collection of the assessments, together with six per cent per annum interest from date of acceptance of the work until paid, and ten per cent of the amount of the judgment, as attorney's fees.