The Gaufre Chantilly is a waffle with whipped cream, and it earns a place in a sandwich catalog the way the folded galette does: it is a batter cooked into bread on an iron, then loaded by hand and eaten without a plate. A waffle batter is pressed in a hot gridded iron until the outside is crisp and the inside stays tender, and the grid is the structural feature. The deep pockets hold the chantilly, the lightly sweetened whipped cream, so the cream sits in the bread rather than sliding off it. It is most often served as a single waffle folded or topped rather than a closed sandwich, but the logic is the sandwich logic: a cooked bread carrying a soft filling, eaten in the hand.
The grid is what makes the pairing work. A flat surface would shed whipped cream; the gaufre's coffered squares trap it and give every bite both the crisp edge of the iron-pressed batter and the cold soft cream from inside the pocket. The contrast is the entire dish: a warm, just-crisp waffle against cool chantilly, sweet but not heavily so, nothing else required to make it complete. It does not keep. The crisp goes soft within minutes and the cream weeps into the batter, so it is eaten immediately, off paper, standing at the stall, which is where it lives, at fairgrounds, markets, and seaside stands across France.
This is a national habit rather than a regional one, and it is the simplest member of the waffle-as-sandwich set: one bread, one filling, eaten warm in the hand. The variations build outward from it by adding to the pocket: chocolate or fruit or other toppings in the broader garnie versions, the denser sugar-studded Liège style as its own base. Those relatives, the waffles loaded and eaten like sandwiches alongside the buckwheat galettes and wheat-flour crêpes of the same hot-iron tradition, are gathered under Crêpe & Galette Salée, and the Gaufre Chantilly is its most pared-down sweet member.