Run your fingers across the wood of the chair to detect any imperfections. Identify the chair as an authentic antique by examining it closely for marks from handcraftsmanship. The process of manufacturing furniture by machines did not begin until the 1860s. A Louis XVI chair will show physical marks from being crafted with a plane, a spokeshave or a draw-knife. The marks may be barely discernible in the wood. The chair may also show straight cut marks.
Look for imperfections in size and shape. A handcrafted Louis XVI chair will differ in size from other Louis XVI chairs and will not be perfectly symmetrical because the chair was entirely handcrafted.
Examine the wood. During the Louis XVI era, the wood of choice was mahogany. It was often finished with a variety of clear finishes. The chair may exhibit leaf or bead mouldings, and classical ornamentation.
Scrutinize the chair's back. It should appear as an oval, rectangular or shield form. An original Louis XVI chair has rosettes and wreaths in squares near the top of each of the chair's straight legs. The decorative rectangular spaces worked into the chair's wood will have classic emblems of the time period.