Earlier quoted context omitted.
It's already true in many places, in a lot of European cities you see a sign like this when entering: https://lsmlomza.pl/pliki/2014/03/lsm-znak1.jpg And it basically means that pedestrians have an absolute priority before cars, they can walk on the street as much as they like and you as a driver have to exhibit some extreme attention because if anything happens, it's 99% certain you will be found at fault.
Is that sign real? It is awful design. The meaning is complete obscure to me.
It's fine. It's just not the kind of sign you are thinking of.
There are at least two kinds of sign.
One kind tells you what the rules are or gives you specific instructions. An example of this kind of sign would be one that tells you that you must wear ear protection, or one that tells you that you must wear a hard hat.
Another kind tells you that you are in a region where a special set of rules apply. Examples are construction zone signs and school zone signs. These signs don't tell you WHAT the rules are, they just tell you that you are entering a place where the rule set changes from one well known set to a different well known set.
From what others have said, it seems this sign is the second kind. It's telling you that you are entering a region where the streets are shared more equally between cars, pedestrians, and playing children than they are in most places, and so you need to follow the rules that apply to such regions instead of the regular traffic rules.