Nineteenth-century France’s fashion for salon chamber music created huge demand for piano duets from even the greatest composers. Playing on an original Erard piano from 1853, Stephanie McCallum and Erin Helyard offer an enticing glimpse into some of these lesser-known duets—charming pieces that would have been lapped up by amateur pianists in homes across France, but which have since barely seen the light of day. It’s endearing stuff, Chausson’s two attractive Sonatines, Ropartz’s intimate 10 Petites pièces, and Chaminade’s ravishing 6 Pièces romantiques among the highlights. Alkan’s whirling “Saltarella,” no doubt, provided a technical challenge for even France’s finest amateur players.