French cutting is based on sculpturing, it is a free hand carving out of hair to the finished detail. It is soft and feminine with flow and movement. It has a natural design by free hand cutting to the contours of the head. It's more cutting by feel or by eye. Scissors and electric clippers or razors are used and any tapering or thining is done after the hair has been dryed. I can do such haircuts in ten to fifteen minutes, by that time the cut is almost dry and very little blow drying without a brush and you have a wash & wear free flowing cut.
English haircutting on the other hand is more like stacking lego blocks, section by section until you have a completed block. The diamond cut which is a Vidal Sassoon technique from the 60s is based very much on architecture, it works very much on the pattern of a spiders web. If you can imagine a spiders web in 3D you can see the lines and sections used in this technique. I find the diamond cut works well on layering and bobs.Blow drying also follows the same routine.
I am not suggesting one is better then the other, French may not suit some people or vise versa. I use both techniques and have also introduced my own style. I cut hair while its flipped over or I may fade with electric clippers on a finished cut whether its long or short.
I do marry my techniques with French and English cutting butas I never use a brush and blow wave by hand, my clients have a maintenance free hair cut that they can manage without any fuss.
French cutting is more widely used on the continent and New York. Here in Sydney it is 90% English cutting. French cutting is a technique rarelytaught in Australia and knowing both techniques is of a great advantage.
You can view a good example of French cutting ---Of all places--- on a Vidal Sassoon TV commercial I did on www.voihaircuts.com.au