From Le Guide Culinaire by Auguste Escoffier first published in 1902:
“French [green] beans are one of the finest of all the vegetables but they need to be prepared with the greatest possible care. Their quality is such that they are nearly always good in spite of the faulty preparation they so often receive.
French [green] beans should be used fresh and must not be cooked for long in boiling salted water. They are best when still a little firm to the bite but not, of course, the least but hard.”