After chasing a few links, the right hand side seems to go according the André Verchuren (also spelled Verschueren) system: D F Ab B D F Ab B C# E G Bb C# E G Bb A C Eb F# A C Eb F# It is like the right hand side of a C-system CBA but with the "wrong" slant of the notes. A diagram with French note names can be found here