The arms and crown are those of a Bourbon legitimate Prince of The Blood Royal, given by two authorities (op. cit.) as 'Le Prince de Dombes'. The present blade type together with the design of the hilt were each altered slightly in 1758 and the regiment re-named.
See Christian Blondieau, Sabre Français 1680-1814, 2002, pp.60-61.
Also see Michel Pétard, Des Sabres et des Épées, Troupes à Cheval- de Louis XIV à l'Empire, vol.1, 1999, pp.72-73, cat.no.53A.