I found him in France, but I am not convinced he is French. A British traveler, or perhaps a gentleman from the Colonial America and pre-Revolutionary era, visiting Paris and adapting to the fashion of the time. The painting dates c.1750-70s, and is a remarkable work of art. The talented miniaturist ha not left a signature (most did not). The painting remains well-protected and pristine in its oval brass mat and protected by the old original convex cover glass, but I feel relatively certain that wood frame dates early to mid-1800s and the painting has been preserved many generations after it was painted. Likewise, the plush claret-red velvet covering the mat is someone's replacement. The presentation works, however, and it's a beautiful wall piece. Some of our doll collectors love this type as room decor and instant ancestors in their doll houses. Full measurements are noted on the photos, but that delicately captured face - it's only 5/8" from chin to hairline.
Very good to excellent condition for age and type - the painting is c.1750-70s and is superb, still with its original oval mat and convex cover glass. The work has been later mounted to velvet on board panel and framed in a mid-1800s gesso appliqué wooden frame, some separation at miter and a little loss. Visually nice, but it is the old painting that carries value. I found him in France.