La. Stat. tit. 33 § 3422
The entire cost of the improvement shall be paid by the owners of real estate abutting thereon, according to the frontage of the property owned by them. If parts of streets or alleys included in a single improvement are of greater or lesser width than other parts, the amount to be paid by abutting property owners shall be proportioned to the varying width. Where a railroad bed or track occupies a portion of a street or alley so improved, the owner of the railway shall pay the entire cost of the improvement of the space occupied by the roadbed, including the extra work made necessary by the presence of the track. In the event the railroad bed or track is owned by the municipality, it shall pay only for the extra work made necessary by the presence of the track.
La. R.S. § 33:3422