Firstly, there's Guylain Vignolles, who is inevitably called (or thought of) as Vilain Guignol (or 'Ugly Clown'), but then that's the luck of the draw if your parents don't think when naming you. Guylain likes reading but his job is with a book-pulping firm, unread literature just being fed into the forever hungry jaws of La Chose, an almost humanised machine that takes on almost symbolic proportions. Some of the people he works with aren't very nice to know, either, such as the harsh boss Kowalski, or the eager kid Brunner, who takes a delight in destroying books. (The guardian Yvon Grimbert, who mainly speaks in alexandrines, is a different case altogether.)
Guylain's consolation comes not so such in talking to his pet goldfish Rouget le Lisle V (yes, there've been four more before and there'll be another later) as reading any pages he's managed to salvage from La Chose (while cleaning it) from his strapontin on the 6h27 RER every morning: he does it for himself more than anyone else, as it gives him a kind of purpose.
Giuseppe is a victim of La Chose, and has lost the best part of his lower limbs to it. His friend Guylain does a lot to help him after the tragedy, although gets a little worried for the state of his mind when Giuseppe says that he'll get his legs back. And in a sense he does: Giuseppe's research reveals that the obscure book Jardins et Potagers d'autrefois (roughly 'Gardens and Kitchen Gardens of Yesteryear') was published on exactly the same day as Giuseppe's accident, so in a very real sense this book must be a part of him. So Guiseppe spends a great deal of time tracking down copies of this book, of which over a thousand copies were printed. But he gets depressed when he can find only over seven hundred of them. And the depression hits him a few months after another of the books are found. But then, secretly, Guylain thinks of contacting the author of the book, who he discovers has died, although he manages to get about a hundred copies of the book from his widow. These he releases very slowly to Guiseppe, aware that one 'found' copy will keep his spirits up for a few months, but that giving him all of them would probably not have a very long effect.
And then one day, on his strapontin, Guylain finds a USB stick, which he discovers contains the wonderful (and somewhat odd) autobiograpical writings of the mysterious young Julie, who is obviously in a similar ill-suited job as Guylain is in: she's a dame-pipi: a (highly articulate) toilet cleaner. And Guylain's in love, but how can he ever find Julie in the whole of Paris? Well, there are some clues, and it's the unemployed Giuseppe who'll read Julie's writings, piece things together from the internet, whittle down the possible places Julie can be working, and from then it's up to Guylain to try his charms out. She's not easy to please, but then they have so much in common... Great book.