Frank Berto describes this model, without the chain retaining device marked 12, as the 1934 two speed Simplex Champion de France. The patent is, slightly confusingly, dated 1932.

One interesting feature of this patent is that it may show the first recognisably modern rear dropout with an integral derailleur hanger.

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• Publisher: L’Institut national de la propriété industrielle
• Inventor: Lucien Juy
• Country: France
• Date: French application March 1932
• Derailleur brands: Simplex
• Derailleurs: Simplex Champion de France