The Frenchie is what happens when a French Euro-nymphing competitor decided a regular pheasant-tail needed more aggression. Same slim silhouette and pheasant-tail body, but with a thread "hot collar" of fluorescent pink or chartreuse just behind the bead — a tiny attractor patch the fish lock onto in fast, broken water.
Sized 12-18 with a 3.0-4.0mm tungsten bead. The bead does the sinking work; the slim body cuts down through the column instead of pushing water like a fluffy nymph.
Fish it on the point or as a heavy dropper on a Euro rig. Hot pink is the universal collar color; chartreuse for stained water; orange for early-spring sucker-spawn windows.