This page, which offers a very nice revue of the Caudron brothers and their G3 aeroplane, does
mention François Durafour, if only briefly.
"The Frenchmen's performance will open the door to many record's attempt, especially in Switzerland where, on July 31, 1921, the
Swiss pilot François Durafour will land with his G.3 on the western slope of the "Mont-Blanc", then took-off a few moments later, what
constituted an uncommon performance."
You can access the page by clicking on the title above.