Maurice LeBlanc's third Arsene Lupin book, L'Aguille creuse, in English The Hollow Needle, was serialized in the magazine Je sais tout in 1908 and 1909, and was brought out in somewhat revised book form shortly after its serialization finished. I know very little about this book; I don't think it's one of the ones I've listened to in audiobook. Nor is it easy to find much definite about it online. What I do know is that in it, Lupin is on the trail of the legendary lost treasure of the Kings of France. His major opponent, Isidore Beautrelet, also is widely considered to be one of the best 'schoolboy detectives' in the genre (he's in high school, and it seems generally agreed that he is both more likable and more plausible than most boy-genius detective characters).