Amédée Courbet
The French expeditionary column commanded by Admiral Amédée Courbet in the Sơn Tây Campaign included four companies of Annamese riflemen from Cochinchina, each attached to a marine infantry battalion. It also included a separate unit of 800 Tonkinese auxiliaries, already called "tirailleurs tonkinois", under the command of "chef de bataillon" Bertaux-Levillain. Many of these Tonkinese auxiliaries were men who had fought with Vlavianos in the autumn battles, who managed to re-enlist in French service after the Yellow Flag battalion was disbanded. Courbet was unable to give these Tonkinese auxiliaries French company captains, and they played little part in the fighting at Phu Sa on 14 December and Son Tay on 16 December. The Annamese riflemen, by contrast, fighting under the command of French officers, distinguished themselves at the capture of the Phu Sa entrenchments.