I think those of us who can answer this inquiry were simply out of town or just plain lazy. :D Rather than type a potted history of this small French firm, I'll simply point you to www.saxpics.com and let you take a look at the Couesnon section on Pete's site. Basically some of the newer vintage Couesnon horns have the classic "Selmer-ish" tone but with slightly less ergonomic keywork. This maker has been making saxophones since the late nineteenth/early 20th century, so there are also early models that are virtually identical to A. Sax's own, original designs. Best of luck.