The Sandwich Kebab is the French döner, and what defines it is the spit, not the bread. A stacked, seasoned cone of meat turns vertically against a heat source; as the outer layer cooks, the cook shaves it off in thin sheets straight into the sandwich. That shave-to-order is the whole mechanism: the meat is cut the moment it is ready, so it stays hot and tender and never sits, and the sandwich is assembled around it on the spot. The build is a warmed flatbread or a split half-baguette, the shaved meat packed in, salad, a white garlic sauce, and, in the French build, a layer of frites loaded inside. The defining element is the vertical spit and the thin shave it produces.
The logic is fast-food architecture tuned for the rush. Shaving in thin sheets keeps the meat tender and lets it pack evenly into the bread instead of clumping; the flatbread is warmed so it folds without cracking and holds heat around the filling, while a split galette or half-baguette is the firmer-handling alternative when the build is heavy. The sauce blanche, a cool garlic-mayonnaise, ties the hot meat to the salad and the chips and keeps the whole thing from drying out. The chips inside do structural work as much as flavor, bulking the sandwich and soaking the juices that would otherwise soften the bread. It does not survive sitting; it is handed over hot and is at its peak within a few minutes of the counter. The cook's job here is steady volume at the lunch and late-night peaks, not refinement.
Variations are mostly the meat and the bread. Lamb at the top end, veal or chicken as the standard, the choice changing how rich it reads; the sauce blanche swapped or doubled with harissa or samouraï for heat; the flatbread wrap traded for the galette fold or the split half-baguette for a firmer hold. The closely related build that leans hardest on the chips-inside move is the Sandwich Grec, which deserves its own article rather than being crowded in here. It belongs with the spit-roasted street sandwiches the catalog groups under Sandwich Grec / Kebab, and its particular contribution is the shave-to-order spit, the mechanism the rest of the build is arranged around.