This shack serves as the residence of the Haitian gang leader, Auntie Poulet. The interior is inaccessible to the player, but the interior of the house can be observed and seen during the cutscenes of Poulet's missions.
In Grand Theft Auto: Vice City, this was the starting place for Poulet's missions. It's the shack where Auntie Poulet gave Tommy Vercetti various tasks that would help her gang in the war between the Cubans, by hexing him with Juju Juice.
The house appears entirely hollow, if viewed from the exteriors of the house. Poulet's house is the lone house that is distinguishable from rest of the houses that neighbor it.