Ah, what a wonderful thread- but it makes me feel all nostalgic... :rolleyes:
Among the very first books I read, there were some Babars, and also the "Barbapapa" series... A bit later, a lot of books by the Comtesse de Ségur (actually some of them were quite dark, with a lot of orphans, abandoned children, early deaths, etc. I felt like crying each time I re-read the moment in "The memories of a donkey" when the darling little mistress of the donkey died from an illness), and also some books of the "Fantômette" series by Georges Chaulet, of the "Club des Cinq" by Enid Blyton (I don't know its English name), the Moomins by Tove Jansson (actually I still re-read those ones from time to time, they're worth reading at any age, and the drawings are so lovely), some Nancy Drew except that in the French version she was called Alice (and the author was called Caroline Quine [sic])... And many books of tales, especially two about Russian and Arabic tales, and several books about Egyptian and Greek mythology (according to my parents, when I first visited the Louvre at 6, it was quite hard to make me exit it because I refused to leave the Egyptian department, as I had been offered my first book about Egypt shortly before

)
I loved the "Little house in the prairie" books too, actually all that sounded so strange and exotic to me (as I had no idea of the place and period it happened); the only one I didn't like much was the last one (at least, the last one published in French) after Laura's marriage, because it was so depressing. My favorite was the one about the long winter, I re-read it again and again...
The first "grown-up" book (not specifically written for children or abridged) I read was a dagger-and-cloark book by Paul Féval called "Le Bossu", I read it when I was about 8 and was quite proud of it- well, actually there were many parts of it that I hadn't understood, as it included some long parts about the history of the Regence (early 18th century period) and its political and economic scandals... But the great duel scenes (ah, Lagardère and the Duke of Nevers in the castle of Caylus...) were enough to please me. Later I would re-read it almost every year, and it was great to understand a bit more of it each time. Well, later I realized that perhaps Féval was not such a great author- however, he was at leasty infinitely better than his son Paul Féval Fils, who wrote some sequels to his fathers' books, and probably is one of the worst author I've ever (to the point that it almost becomes comical). By the way, there have been several films after "Le Bossu", but for me none of them is satisfying (especially that they all have forgotten much of the story and many characters).
I also loved Stevenson's "Treasure Island" (in general, I was quite fond of anything with pirates and islands). And there were all the "classical" French-Belgian comics, like Tintin, Astérix, Lucky Luke, Gaston Lagaffe... A bit later, I started reading a lot of Agatha Christie books at my Junior high school's library, and also quite a lot of Dumas (with a fondness for "The Three Musketeers" and "Joseph Balsamo"- by the way, there are some lovely pages by Stevenson about how much he enjoyed re-reading Dumas' books)
and some Jules Verne (and also some adventure novels of the "Signe de pistes" collection). Then, when I was about 11 or 12, I started reading a lot of science-fiction, especially Asimov and Sheckley, and also "Wuthering Heights" which started a period when I tried to read everything I could find by and about the Brontë family.
When I was around 15 I became interested in Carson McCullers and Stefan Zweig (strangely, those are associated in my mind , because I was given a book by each for a birthday by my aunt), and also, in a less serious style, all the Arsène Lupin and Sherlock Holmes books, and some French popular novels of the 19th century (Eugène Sue, Michel Zévaco...), and some Daphné du Maurier (with a special fondness for "Rebecca" and "The King's General"). It reminds me of a friend of mine who really didn't like reading, I had convinced her to try some Du Maurier, and her mother was baffled to see that she even was reading it during dinner- and she bought be a new copy of "Jamaica Inn", because the one I had lent her had fallen in her bath when she was reading it... Unfortunately, we lost contact shortly after that, so I couldn't continue that "experiment".

I also loved quite a lot "Les Misérables"(realizing that it was far bigger than the abridged version I had read as a kid...)