Doorbells and letter boxes

In Britain, if you want to send something to someone who lives less than 15 minutes away from your house, you generally don't bother posting it. Even though you know that if you did, by first class it would definitely get there the next day. So you pop on your bike or your own two feet, and slip it through the letterbox of the house they live in. If they live in a block of flats, there is still, usually, some kind of general letterbox that gets sorted later, or at the most awkward, a doorbell marked "traders" or "postman".
In Italy, people often had their letter boxes outside, and if they didn't, there was some kind of general hole through which you could put things, for the whole building.
In France, despite the fact that the postal service is useless and won't get your letter there the next day unless you pay them €30 at least, people don't ever seem to deliver by hand, or at least, if they do, I'm flummoxed as to how. Letter boxes are in the main hallway, inside the main entrance door. Usually the postman has a key, or knows the code to each building. If not, as here, he has to ring the bell for every flat until he finds someone in who can open the door for him. But an individual wanting to deliver something is stuck–there is no "let me in please" bell, and often not even named bells but just some numbered bells or worse still, just a number pad for an entrance code you don't know. So you end up standing around outside wondering when someone will turn up and open the door for you–hence my conclusion that they must just never deliver things! How odd.