Sandwich à emporter is the French label for the sandwich made to leave the counter: not a recipe but a format, the takeaway sandwich packaged for transport and eaten somewhere other than where it was assembled. It is what is written on the boulangerie case, the station kiosk, the market stall, the office-run order. The contents can be almost anything the counter sells, baguette with ham and butter, a filled half-loaf, a wrapped roll, but the defining trait is the wrapping and the gap in time between assembly and the first bite. The sandwich is built to be carried.
That gap is the entire design problem. A sandwich eaten on the spot can be soft, juicy, freshly sauced, and fragile, because it only has to survive the walk to a table. A sandwich à emporter has to survive a paper sleeve or a sealed wedge of plastic, a bag, a commute, and a stretch of time in which condensation collects against the crumb. So the format quietly shapes the contents: the bread is chosen for how it holds rather than how it eats warm, wet elements are kept off the crust or omitted, butter or another fat is used as a moisture barrier between filling and bread, and the assembly is squared off to pack flat. The good versions account for the journey and arrive intact. The bad ones are the ones that have sat in a refrigerated case since the morning and have given their texture up to the wrapping long before anyone opens them.
There are no variations to enumerate here, because the variations are every other sandwich in the catalog seen through the lens of portability: the question is not what is inside but whether what is inside can stand the wait. That is also why the format separates the careful counters from the careless ones. A boulangerie that wraps a fresh baguette to order and a station case that filled its wedges before dawn are selling the same nominal thing under the same three words, and the difference is entirely in how much they respected the gap between counter and mouth. The Sandwich à Emporter belongs with the broader French catalog the site groups under Regional Specialty Sandwiches, the wide shelf of named French sandwiches; it is the cross-cutting format almost all of them eventually have to pass through.