In The Shadow of the Wind by Carlos Ruiz Zafón, Zafón has the main character discover a book entitled The Shadow of the Wind in the Cemetery of the Forgotten Books. This book is by a little-known author, Julián Carax, who was not very well-received by critics and many of his books have been destroyed following his death in either Paris or Barcelona following the Spanish Civil War. Is Julián Carax based on a real person or is he a character entirely his own?
Interesting question, I wondered myself. All I could find was a small hint in "Julian's book", the last chapter in "The Labyrinth of the light" (1:1 translation from my German copy, the original was published in 2016 as "El laberinto de los espíritus".
There's a name mentioned as ghostwriter of Julian Carax: Boris Laurent. This could be some inside joke or a hint, as such a person(s) actually exist(ed). One of which has written 3 books (found at Amazon), but since I don't understand Spain nor French I have no idea if this reference could actually point to a real person. Very vague, very conspirative, I'm still sitting in the dark. Could be just a common and garden name...
But Julian Carax is most certainly a fictive name.