I don't recognize this portrait specifically, but I can tell you a few things about it that may help to identify the sitter. Given the style of the wig - powdered and light-colored, long and curled, with a little height and a center part - and his neckwear, this was most likely painted in the early 18th century, probably around 1710. Given that he is painted in armor and wearing the cordon blue signifying the French Ordre du Saint-Esprit, he must be quite high-ranking.

Facially, he looks very much like Louis XIV: compare the features to this portrait of him by Hyacinth Rigaud from 1701. Long, downward-pointing nose; thin lips; cleft chin. Considering that Louis died in 1715, it's very possible that this is a portrait of him.