Caraway and a clear note of cumin run under the smoke, and that spicing is what sets this Franc-Comtois cooking sausage apart from its larger neighbour. The saucisse de Montbéliard is a slim pork sausage, coarsely ground, seasoned with caraway and a clear note of cumin, then smoked slowly over resinous wood until the casing takes a deep colour and a firm snap. It is poached or simmered through before it goes anywhere near bread. The build is a sturdy crusted loaf split lengthwise, a thin spread of butter if anything, the cooked sausage sliced on the bias or split lengthways and laid along the crumb, with little else so the spiced smoke is the whole sandwich.
The logic follows from the seasoning and the format. The Montbéliard is the slimmer, more aromatic Franc-Comtois sausage: the caraway and cumin give it a warm spiced lift the plainer regional sausages lack, and the smoke sits over that rather than dominating it, so the sandwich reads fragrant as much as savoury. Because the sausage is narrow, it slices into neat coins or splits cleanly into two long halves that lie flat on the bread, giving defined bites rather than a crumble. The constraint is to keep the build quiet: it is salty, fatty, and already complex from the spice and the wood, so a strong condiment competes instead of completing, and a stripe of strong mustard or a few cornichons is the most it wants. The sausage is best sliced from a piece cooked through and still warm, when the fat is supple and the cumin is forward; gone cold and firm against the crust it tightens and the spice recedes. The bread needs a real crust because the filling brings no structure of its own.
Variations stay inside the Franche-Comté larder rather than wandering off it. The larger, plainer, wood-pegged Morteau is the closely related benchmark, treated as the Sandwich Saucisse de Morteau, denser and woodier where the Montbéliard is slimmer and spiced; a slice or shaving of the region's hard mountain cheese laid alongside is the classic Comté pairing, read separately as the Sandwich Comté-Saucisse de Morteau. Each holds the smoked Franc-Comtois sausage as the fixed point and changes only the size, the spicing, or what sits beside it. It belongs with the cured-meat sandwiches the catalog groups under Sandwich Saucisson & Charcuterie. Its specific contribution is the slim, caraway-and-cumin-spiced smoked sausage, the more aromatic of the Franc-Comtois pair.