Just to add my ideas to this discussion, I think the officer is indeed French or a Napoleonic 1st Empire ally of France and the medal on his chest together with the Legion of Honour is The Saint Helena medal, created in 1857 by Napoleon III,and awarded to the 405,000 soldiers still living in 1857, who had fought with Napoleon I during the 1792-1815 wars.
http://www.stehelene.org/php/accueil.php?page=1&lang=en
Ian
P.s. The ribbon on my Sainte Helena medal is a replacement.