Oh my gosh, fantastic duo, they play in B (that is, H in German terminology and SI in French/Italian) half tone deeper than C, I guess the base note on Jean-Claude Rocher's cabrett is F# (FA#). So much for the myth, that G/C is the standard tuning of cabrette music :D. Possibly M. Rocher has a GC pied, too, but here he picked an F#/B pied. On the CBA any keys are equel until A is 440Hz..