The first assistant district attorney for the Ninth Judicial District shall receive as compensation for his services, in addition to the annual salary paid him by the state, an annual salary of not less than seven thousand dollars, as established from time to time by the governing authority of the parish of Rapides, the amount so established to be payable monthly on his warrant by the said parish. Any salary increase made as permitted herein by the governing authorities of the parish of Rapides which shall remain in effect six months as to any particular assistant shall not be reduced thereafter.
La. R.S. § 16:222