I have long ago found the French nymphing style a useful backup option for the times when fish are not responding to the dry fly. It has served me well especially in the very early and very late parts of the season, when the water is cold and fish reluctant to rise.
I have recently come to have doubts about the "Frenchness" of my approach: I was taught the technique by true masters, who surely forgot more about nymph fishing than I can ever hope to learn. But while all of them knew well the way of the nymph none were particularly strong in foreign languages, and I am positively sure none of them understands a word in French. So the technique I am about to describe might have been French at its start, but has passed through so many Czech hands that I am unsure how much of its origin remains.
The key part of the technique is the indicator. Unencumbered by the arcane requirements of the FIPS Mouche competition rules I have found that the simplest home made indicator works the best for me. I am using a short length of braided Dacron fly line backing in bright orange color. It has a perfection loop tied on each end and when treated with red Mucilin it floats like a piece of cork.
The indicator is loop to loop attached to a level 0.30 mm Stroft monofilament leader some 6 meters long. The weight of the indicator and flies attached is sufficient to cast this leader to the distance of around two rod lenghts, which is OK for my kind of fishing.
At the other loop is attached the tippet, again using the reliable loop to loop connection. For most of my fishing I am using 0.16 mm Fluorocarbon tippet. I try to avoid lighter tippets for nymph fishing whenever possible, as any bottom snags with a 7X tippet are likely to result in loss of whole team.
On the tippet I tie my team of flies. I always fish with two flies, a heavier one on the point and a smaller one on dropper. I adjust the length of my tippet according to the depth of the water I fish, aiming for approximately one meter long tippet in knee deep water.
The point fly serves several purposes - it adds weight to the team so I can cast it further, helps to straighten the leader and drags the lighter fly to river bottom. Actual fish catching is secondary. The smaller fly on dropper does most of the work and accounts for about two thirds of the fish taken.
An example of the point fly is the Heron Goldie fly above, tied with 3.3 mm Tungsten bead.
Examples of the dropper flies are a #16 Motley Turkey nymph with a 2.4 mm Brass bead and a #18 Crane feather nymph with a 2.0 mm Brass bead.
All the flies are tied to similar pattern - tail of rooster hackle fibers, contrasting tag of pink, orange or chartreuse thread, body of nondescript color with a furry thorax and a metal bead. I tie my point flies with Tungsten and the dropper ones with Brass - the additional weight of the dropper fly is small, but the difference between cost of a Brass and Tungsten beads is large.
I found that the choice of fly rod for nymph fishing matters less that the tackle manufacturers would like us to believe. Fly fishermen who specialize in nymphing like to use long wimpy rods - 10' to 11' in length of the AFTMA class 2 or 3. These indeed do the job, but are impractical for any other fly fishing technique, especially if overhanging vegetation is involved.
I have the French leader and a box of beadheads stowed in reserve in my fly fishing bag, and whenever situation demands so I rig them on my 8'6" AFTMA 4 class dry fly rod. There are times when I wish for a longer reach, but overall this method serves me just fine.