Pork sets the baseline every other rillettes sandwich is read against. Rillettes de porc are pork shoulder and belly cooked slowly in their own fat until the meat breaks into soft strands and binds with that fat into a pale, coarse-grained paste, fatty by design and forthright in flavor. This is the default the word rillettes points to before any other animal is named: the spread is loose, generous, faintly peppery, and warm-tasting from the long cook. The build is a crusted baguette, split, a thick layer of pork rillettes worked into the crumb, and little else, so the potted pork is the whole sandwich.
The logic follows from the fat. Pork rillettes carry their richness through every gram, so the sandwich needs no butter and no melted cheese to feel substantial; the paste is the filling and the binder at once, pressing into the open crumb and holding the loaf together as one mass. That richness sets the constraint. It is salty and dense enough that the build stays lean and the counterweight stays sharp, a few cornichons or a stripe of strong mustard cutting the fat the way they do on a charcuterie board. The bread has to have a real crust, because a soft loaf collapses under a heavy, yielding spread that offers no structure of its own. It eats cool and best at room temperature, where the fat is soft and carries; chilled hard, the rillettes turn waxy and the loaf goes leaden.
Variations sit on the same shelf and mostly change the grain and the cut. A coarser, fattier pork pack reads richer and looser; a finer one spreads tighter and cleaner; a drier, longer-cooked Touraine version is a recognized step of its own. Each holds the potted, shredded pork as the fixed point and changes only its texture or what sharpens it. The Sandwich Rillettes de Porc belongs with the cured-meat sandwiches the catalog groups under Sandwich Saucisson & Charcuterie, the tradition that runs across France's regional curing shelves. Its specific contribution is the default rillettes, the fatty, coarse-grained pork spread that every other version is measured against.