One cannot call Belgrade a child-friendly city. I have yet to see a restaurant with a changing table or a policeman who will keep Belgrade drivers from parking on the sidewalks, not forcing mothers with strollers to sway into the streets and take it up with cars, trucks and buses.
No bus is equipped for strollers; not only are they always over-crowded but one would not fit through the doors. Aisles in supermarkets are so narrow that one better leaves the kid at home. I'm not even mentioning the bad air quality outside and the much worse air quality in restaurants, cafés or trains. Serbians are very Balkan when it comes to smoking.
However, in other respects Belgrade is the most child-friendly city I've ever been to.
Mothers are always whisked to the front of any queue, be it at the post office, the bank or in a restaurant. Everybody, from teenage boy to old woman, will hold doors open for you and offer to help you carry the stroller up or down the stairs while complimenting you on your sweet offspring.
No, it's true - even teenagers flirt with your baby when you're waiting at the traffic lights. No German or American teenage boy who has an ounce of self-respect would ever be caught doing that. Sellers on the market will give you free bananas and free advice on shoes and hats (both always obligatory on Serbian children, no matter age or climatic conditions).
I prefer this way of being child-friendly to the omnipresent Koala bear changing station in the States or Germany.