Ce site philatélique donne toutes les informations connues sur le timbre 0,50F Marianne de Béquet en les illustrant.

This website is dedicated to only one french stamp: the red 0,50F Marianne de Béquet. It can seem surprising because this stamp only occupies two or three lines in non-specialized catalogs. Nevertheless, as I will try to show, this study led me to a wide spectrum, complex and however fascinating search, that is not likely to end soon.
It should be noted that this stamp was printed during a pivotal period for definitive stamps in France:
definitive implementation of two-tiered postal (...)