In Italy we call it -Curvilineo-
This tool to draw curves was used by taylors from long,long time



Actually they are still using to make or modify models or create shapes and angles of the body
There is a French curve (Curvilineo spalla-shoulder) to make upper part of the body(holes for neck,arms and belly)
there is also a Hip curve (Curvilineo fianchi-hips) to make lower part of the body (skirts,trousers)
Maybe...i say maybe...this taylor's tool was called French curves like a tribute to France..being,in the past,wordwide reference of fashion
Pardon monsieur Pilou,but nowadays references of fashion are changed,so.....we could call it "Italian curve" ;) :) :)