Gaston Clément describes the Concours des Voges, a reliability trial over 1,000 km and 11,500m of climbing, held between the 11th and the 18th of July in 1920. Paul de Vivie is mentioned as a kind of patron saint of the event.
My french isn’t very precise, but I think that 10 competitors completed the trial riding a total of 8 machines (2 machines were tandems). Of these 8 machines the ‘overall winner’ was an Audouard equipped with an Audouard 4 speed derailleur system. The other seven machines were all fitted with Le Chemineau derailleurs. Of these seven, two were described as ‘Tandem Panel’ and were fitted with six speed systems, four were ‘Bicyclette Panel‘ fitted with 3 speed systems, and one was a Desvages solo fitted with a 6 speed Le Chemineau system. It is interesting that the author considered ‘Panel’ to be a bicycle brand. Joanny Panel was, of course, the manufacturer of Le Chemineau bicycles and derailleurs. On all the frames that I have seen, and on all the bicycle brochures that I am aware of, the branding is clearly ‘Le Chemineau’.
One of the ‘Tandems Panel’ that completed the trial was ridden by a ‘M. and Mme. Joanny’ - which is likely to refer to Joanny Panel and his wife.
The Desvages model was ridden by a ‘M. Desvages’. Pierre Desvages was a bicycle maker from Paris who had a long association with Le Chemineau. Later on, he took out a license to fit Le Chemineau derailleurs to his machines and branded these derailleurs as ‘Desvages’.
(Source gallica.bnf.fr/ Bibliothèque nationale de France)