« Arsène Lupin, le gentilhomme-cambrioleur »
The nice thing about ebooks is that they come from all over the world. It's ridiculously difficult to get foreign-language works in the US. If it ain't English, it ain't here. There are the occasional exceptions, but you really have to get up to the notoriety of "The Little Prince" or "Don Quixote" before anyone will stock a work in anything but the English translation.
Consequently, a lot of the stuff I read, I can only get by shipping things from halfway around the world, or electronically. I do the former occasionally; one of the most expensive non-class books I've ever bought was a first-edition printing of „Die unendliche Geschichte”, the original source of "The Neverending Story" that was made into the film I remember so fondly from my childhood. It's a beautiful piece on its own -- the German edition is printed in green and black, will full-page illuminated capitals at the start of each chapter. I have another Ende book also, the less-elaborate but no less charming „Momo”, which is printed entirely in chocolate brown.
Unfortunately, when you read as much random stuff as I do, this quickly becomes an extremely expensive habit. Fortunately, I have a taste for Victorian detective novels, most of which are now available free of charge. The Gutenberg Project is hosted in the US and adheres to US copyright laws unless explicitly told otherwise; US law is hideous and complicated, and has been subjected to much monkeying around over the years, but any copyrighted work published here prior to 1923 is considered to be in the public domain. All but the last volume of the Sherlock Holmes stories are public domain, for instance, as is everything written by Poe, about half of G K Chesterton's Father Brown stories, and a whopping load of so-called "penny dreadfuls", published throughout the country from the 1880s on.
French copyright law holds that the works of an author remain under copyright until 70 years after the author's death, which means that on December 31, 2011, all of the works of a man named Maurice Leblanc passed into the public domain. Leblanc, I find, is almost unknown to the English-speaking world, which is a damnable shame, because his Arsène Lupin stories are wonderful, wonderful things. Arsène Lupin, "gentleman burglar", as he is usually described, is dashing, daring, clever above all else, and possessed of a very wicked sense of humor, which usually manifests itself as being audaciously polite when explaining to people how he has pulled one over on them and why they can't do anything about it.
Many have borrowed from Leblanc. If you pay attention to Japanese animation, you may be familiar with a series called Lupin the Third, which chronicles the continuing adventure of the grandson of the famous thief. The manga is rather brasher than the original, but the anime captures the spirit fairly well. Even more faithful spiritual descendants are Leslie Charteris' Saint novels (started 1928 with "Meet The Tiger") and Harry Harrison's Stainless Steel Rat series (started 1961 with "The Stainless Steel Rat").
Leblanc himself borrowed from his contemporaries. He wrote the Lupin stories from 1906 onward, which puts him roughly even with Sir Arthur Conan Doyle; and like Sir Arthur, there was a time when he resented that his creation had taken on a life of his own. Lupin's tales, too, are set down by a biographer, but instead of writing an assistant for him, Leblanc appears as the narrator, as a fictionalized version of "himself". Occasionally Lupin makes a first-person appearance, where his inner voice is as flippant as the exterior description.
I'm not sure how to rank the difficulty of reading Leblanc for non-native speakers. Certainly you need French sufficient for reading novels without checking every third word in the dictionary, but whether you need more than that depends on how you deal with vocabulary. If you memorize whole words, you may do a lot of stumbling. You won't find the word "démeublier" in a dictionary, but "defurnishing" a château is in fact exactly what Arsène does in an early chapter of the first book. If you are at ease with taking words apart at their logical boundaries and putting them back together in different configurations, you'll be fine.