For use as a green bean, they need to be picked when young, or they will become fibrous and stringy. They really need to be picked every day.
If left to fully mature you can use the beans inside as dried beans.
When Fin de Bagnols Beans are fully mature, the pods will turn red to light brown, and will be long, rounded and very slender.
Fin de Bagnols Beans are a variety developed in France in the 1800s. They were introduced in 1957 by Pucel Camut.