Really nice indeed! This shape is what we call "violon" (violin in english). The wood seems to be ebony, right? It seems there is a nice file work also (in french, we call it "guillochage"), could you show us a picture of it? I guess this is a slip joint, not a "cran forcé" (i still don't know any translation, see post #22, page 2 on this thread).
And now, a tip for you american guys, not extremly used to slip joints and crans forcés: as there is a spring that makes the blade slam, there always have to be a space between the blade and the spring, so the edge is not damaged by hitting the spring. We call this "poncetage" (don't know the translation either), and you can check your knives when the blade is closed, just by pushing on it. If the knife is well made, the poncetage is hard and the gap relatively important (2-3mm, not possible on some knives though). A knife without poncetage will damage the edge easily, making a typical rounded dent in it. I will post a sketch to explain it (and how it works), but right now i have to go.