The exterior scenes are shot on the "European Street" backlot later used as the holodeck village of Fair Haven, Ireland in the Star Trek: Voyager episodes "Fair Haven"(S06E11) and "Spirit Folk," (S06E17) as well as the village of Sainte Claire, France in "The Killing Game" S04E18 and "The Killing Game Part II" S04E19.
Even though set in New Orleans, no filming was actually done there.
The Voodoo episode. In the 70s, most popular TV shows all seemed to have one Voodoo-themed episode. This one, however, doesn't have much atmosphere nor "Voodoo" elements to it. There are 2 brief scenes taking place in a shop where African wood statuettes are seen in the background (1 scene only) but no Voodoo dolls are shown; and a couple of very brief scenes where Yvette is performing incantations on a cloth doll serving as Voodoo doll.