Very rare and unique pocket watch case with two back covers that are hinged.  I suspect the inside cover was used as a mirror since it is highly polished.  Glass on front shows some light scratches.  Case is missing the top 'buttons'.  Not sure of case metal.  It is not magnetic so I suspect it is nickel or silver plated (not sure).  Inside of 1st cover is marked "Made in France".  Measures 1 7/8 inch in outside diameter.