Patricia Petibon’s new album is a bit of a puzzle. The basic idea is fine: the maverick soprano undertakes a survey of 20th-century French song that embraces everything from classics by Fauré and Reynaldo Hahn to 1960s chansons written for Juliette Gréco, her point being that the boundaries between “serious” and “popular” culture aren’t always easy to define. Unfortunately, she doesn’t always play it straight. Quite a few of the songs come in fussy arrangements so as to cater for the clutch of guest instrumentalists drafted in to join Petibon’s regular accompanist, the admirable Susan Manoff. So Satie’s delicious Je Te Veux acquires an unnecessary cello obbligato; Manuel Rosenthal’s songs are tarted up with intrusively clattering percussion; actor-director Olivier Py turns up for a duet in which he and Petibon use silly voices; and so it goes on. On the occasions when all this claptrap is jettisoned, Petibon proves utterly beguiling, particularly in Hahn, while Manoff’s playing is impeccably stylish throughout. But overall, this is inconsequential and rather disappointing.