This photo features Jules Dubois at the 1923 Championnat de la Bicyclette Polymultipliée. Jules was a regular competitor in these events and often came away with some kind of prize for the oldest, wisest or generally most venerable competitor.
He was riding an RPF bicycle fitted with a l'As 2 speed rear derailleur and a double chainwheel. This rear derailleur was operated by back-pedalling, and required no cable - and indeed, you cannot see any cable in the close-up. However he does have a gear lever on his top tube, probably for a front derailleur.
The bubbling emulsion and Jules' splendid moustache add a certain period charm to the image.
(Source gallica.bnf.fr/ Bibliothèque nationale de France)