One has to bear in mind that Berbiguier was an outsider in France, as he preferred a powerful tone even in low flute registers. Thus, his tonal concept was quite different from the one favoured by other flutists. He therefore rather used the English tone ideal characterised mainly by Ch. Nicholson. Berbiguier's catalogue of works is quite extensive: 11 flute concertos, more than 140 duets for 2 flutes, about 30 trios for 3 flutes, the inevitable "Variations on ...", études still used for instruction today, and a flute tutor.
Difficulty level, roughly compared to ABRSM exam grades. 0 is beginner, 9 is advanced (beyond grade 8).