After the rampant complexity of their 1958 Allvit, Huret went all out for simplicity with the 1963 Huret Svelto. It was a pared-down, all-steel economy model that was cheap to manufacture, sold in millions and had any number of imitators.
It worked OK when new, but the parallelogram lacked the torsional rigidity of more three dimensional designs, and the pivots quickly loosened destroying any pretense at precision - not so much of a problem when your main competition is the 1962 Simplex Prestige - but a serious short coming when you are up against a 1967 Shimano Skylark.