In Paris pavements are routinely lined with stacks of books, magazines, comics, etc. The idea being 'you take some, you leave some. Or just take, at least the books will find some use.' I've seen it abroad so it's probably widespread.

Slightly more tangential, but people also often leave furniture (or clothes) they don't need outside for the taking, often because they're moving places. You notify the municipality, put up a post-it with a number on it so that they can eventually identify and carry the stuff away if it finds to takers, but in the meantime other people are free to help themselves. I have friends who would completely furnished their apartment with furniture found on the street.