The Clair brothers were three men from Saint Etienne, France – Benoit, Jean Baptiste, and Victor Clair. They submitted their first patent in 1889, which described in general a gas-operating system for firearms. This was followed by a British patent (#15,833) in 1893 for their system, which they claimed was applicable to anything from a pistol up to a rifle, Gatling-style large gun, or even cannon. We know that they did apply the design to shotguns (like the one in today’s video), rifles, and handguns. At least one functional example of their pistol was built, because it was tested (unsuccessfully) against the French Mle 1892 revolver. The basic system is a long stroke gas pistol system and a magazine extending from the action backwards into the stock. For more information on Clair firearms, see my previous blog post on the Clair self-loading pistol.
Thanks to the Liege Arms Museum for access to film this for you! If you are in Belgium, definitely plan to stop into the museum, part of the Grand Curtius. They have a very good selection of interesting and unusual arms on display.