Cut this cheese and it keeps moving, so the sandwich has to be assembled with a runaway in mind. A ripe Camembert from Normandy has a soft white bloomy rind and a paste that runs toward liquid at the center when it is at room temperature, so a wedge laid into bread does not sit still the way a hard cheese does: it slumps, spreads against the crumb, and pushes toward the crust. The build is a length of baguette, a thin spread of beurre demi-sel, and thick wedges of Camembert laid rind and all along the bread, the rind kept on because it carries most of the cheese's mushroomy, faintly ammoniated edge.
The logic of the sandwich follows from how the paste behaves. Because a ripe Camembert is already close to spreadable, it needs no help being rich, and the work is in containment rather than addition. The crust of the baguette has to be firm enough to hold a cheese that is trying to leave, and the butter is kept thin because the paste is doing the job butter usually does. A wedge cut while the cheese is still cold and chalky at the core gives a denser, drier sandwich with a tighter bite; a wedge from a fully ripe wheel gives a soft, oozing one that wants to be eaten standing over a plate. Restraint is the discipline: a few slices of ripe pear or a single green apple baton sharpen the cheese without competing with it, and most additions past that fight the rind for control of the flavor.
The bread needs a real crust because the filling brings no structure of its own, and the cheese needs to be near room temperature because cold Camembert reads as bland and faintly soapy while a ripe one tastes of cream, mushroom, and barnyard. It is a sandwich best eaten within minutes of assembly, before the paste fully soaks the crumb and the baguette gives up its bite.
Variations stay on the soft bloomy-rind rack: a wedge of Coulommiers for a milder, less assertive paste, a young Brie for a flatter and creamier reading, or a slick of fig or apple between cheese and bread when the wheel is very ripe and needs a sweet counterweight. Each is a swap of one soft rind for another, the bread and the restraint held constant. It belongs with the cheese sandwiches the catalog groups under Baguette Fromage, and its specific contribution is a cheese that behaves like a thick spread the moment it warms, so the sandwich's job is to hold it together.