Really? I’ve been there many times and have never noticed. Maybe it’s a newer trend?

It's not a new trend. People in latin countries like to look at what is happening on the street. https://www.alamy.com/stock-photo/paris-cafe-1950s.html

You have the right username to know Paris ;-) I can't remember from my own visits to Barcelona and Belgium how common it is. But photos of 1950s Paris are not evidence that it's common in other cities now.

I’ve lived all over the place in France and also in London and I’ve only seen this in Paris.