In many ways, the Commerce is a smaller version of Mother's, but without the lines. It offers a full assortment of poor boy sandwiches, plus all the Creole platters you'd expect of a place serving quick lunches for people with less time than hunger, but with better food than most such places.
The Commerce opened some fifty years ago, when the Central Business District was indeed full of both business and commerce. Then as now, it has been a source of quick lunches for people with less time than hunger, but with better food than most such places. Although it was renovated a bit after Katrina, it's little changed since I first went there in the 1960s and 1970s--the same line, the same tile floor, same menu more or less.
One large, long room with a tile floor, a high ceiling, and big windows creating a bright aspect. A small cafeteria line runs along one wall, with tables along the windows. The place is a bit torn, but in a comfortable way.
Know that the roast beef here is more cut into chunks than sliced; that's an issue with some people. Tell them to go easy on the gravy; they really lay it on. If you try to avoid the crowds, it's better to go early than late.