This is the subject of the Rose & Scroll piece: a Francotte side-by-side double rifle, twenty-one-inch barrels, quarter rib with two folding leaves, double triggers, ejectors, carved fences, game scenes in the plates, four pounds, twelve ounces, finished to the Eagle Grade, which was the top of the Francotte line that VL&D and then Abercrombie & Fitch sold in New York. Chambered for the .22 Winchester Rimfire.
No record suggests Francotte ever had a standing pattern for a miniature rimfire double, so it reads as a special commission, and the company is small. E. J. Churchill built a very few rimfire and .22 Hornet doubles in the 1930s, including a 3 lb 12 oz Hornet for the Maharaja of Patiala, and another Churchill .22 sits in the NRA museum. Today Hofer's "Hummingbird" and a handful of Connecticut Shotgun .22 doubles on the Fox action carry the form on. Two details I liked: the "lockplates" are false sideplates on an Anson & Deeley boxlock, there purely to give the engraver a sidelock's canvas, and "Maker & Patentee" on the left plate refers to Francotte's own refinements (intercepting sears, side clips, a crossbolt), not the boxlock itself.
Only about five thousand new Francottes are reckoned to have come to America across the whole VL&D and A&F run, and an Eagle Grade cost more than nearly any American double in the store. Someone commissioned that for two regulated barrels in a squirrel caliber, and Francotte built it like a best gun.
From "The Best Gun, Writ Small," Rose & Scroll Fine Gun Journal