From the Earth Architecture website:
A series of wood bars, set between the posts, helped to hold the plaster in place. Bousillage, molded into bricks, was also used as infilling between posts; then called briquette-entre-poteaux. The bousillage formed a solid mud wall that was plastered and then painted. The bousillage also formed a very effective insulation.
The tradition was brought to New Orleans from France by the Acadienne. The technique also has Native American influences. This paper describes how “When the French built in Louisiana, their earliest houses were of this frame structure, but with the post in the ground. Sometimes the post were placed close together palisade fashion.