La. R.S. 33:140.21

After the commission has recommended and the city council has adopted a master plan which includes at least a major street plan, or the commission has progressed in its master planning to the state of the making and recommending of a major street plan, and shall have certified a copy of such major street plan to the city council, then the city council may establish an official map of the municipality. The official map shall show the location of the streets theretofore existing and established by law as public streets. Such official map may also show the location of the lines of streets on plats of subdivisions which have been approved by the commission. The city council shall certify the fact of the establishment of the official map to the clerk of court of Caddo Parish.