Fine 18k Gold Locket Frame, 2 French Portrait Miniatures, Magistrate and His Wife, c.1750-70

A rare find, and a magnificent personal pair of portrait miniatures, husband and wife, one on each side of the pendant or locket-like frame mount of 18k gold. A distinguished couple who are not identified, he wears the powdered hair and red robe of a judge or perhaps attorney, avocat, or magistrate in his time. Not quite nobility, but moving in close circles and obviously this has been a very well-kept and treasured heirloom or museum piece. The thick gold mount has been acid-tested and confirmed at 18k, but I do not find the typical French marks, so perhaps not from France. Thick and convex original cover glass remain on each side and are each clean.  I was going to try to pry open the 2 halves just to see if more ID or artist information might possibly be inside, but it doesn't pry easily and I didn't want to damage it in any way trying. It may turn out that there will be more information within. The paintings are small masterpieces, each very detailed face being only 1/2" or slightl