This advert offers a special racing bicycle named for the ‘Circuit des Champs de Bataille’. This gruelling 2,000 km stage race was held in 1919 and literally toured the great battlefields of the First World War - a physically and emotionally draining ordeal for riders who had lost friends and relatives. The ‘Le Chemineau’ was the only derailleur-equipped bicycle to complete the course.
Also mentioned is the Bordeaux-Paris race of 1919, ridden by ‘père’ Desvages. Over the next decade or so you often see adverts for ‘Desvages’ bicycles fitted with Le Chemineau derailleurs.
(Source gallica.bnf.fr/ Bibliothèque nationale de France)