Boardgamegeek https://boardgamegeek.com/boardgameexpansion/324656/war-chest-siege
English - Not all battles are fought on the open field. In many cases defenders hide behind the thick walls of mighty castles. Now is the time to prepare for Siege! As castles grew larger and stronger throughout the middle ages, new ways evolved to scale, knock down, and even undermine their walls.
Official https://www.gigamic.com/jeu/champ-dhonneur-extension-siege
French - L’extension Siège propose un nouveau type de tactique, un nouveau type de pièce et de nouvelles unités.