“ After the Restoration Louis XVIII. wished to give Haxo a command in the Royal Guards, but the general remained faithful to Napoleon, and in the Hundred Days laid out the provisional fortifications of Paris and fought at Waterloo. It was, however, after the second Restoration that the best work of his career as a military engineer was done. ”

“ Soon after this came the French intervention in Belgium and the famous scientific siege of Antwerp citadel. Under Marshal Gérard Haxo directed the besiegers and completely outmatched the opposing engineers, the fortress being reduced to surrender after a siege of a little more than three weeks (December 23, 1832) . He was after this regarded as the first engineer in Europe, and his latter years were spent in urging upon the government and the French people the fortification of Paris and Lyons, a project which was partly realized in his time and after his death fully carried out. ”