La. Stat. tit. 33 § 2485
The title of each class shall be the official title of every position allocated to the class, for all purposes having to do with the position as such, and shall be used to the exclusion of all other titles on all pay rolls, budget estimates, and official records and reports pertaining to the position, except that any abbreviation or code symbol approved by the board may be used to designate a position of a class. Any other title satisfactory to the appointing authority may be used in official correspondence and in any other connection not having to do with the personnel processes covered by this Part. No employee shall be appointed, employed, or paid under any title other than that of the class to which the position occupied by him is allocated.
La. R.S. § 33:2485