It will get worse. You rarely see fat children with skinny parents. But a lot of fat parents have fat kids too. Once these grow up it will be more and more likely that their children will get fat too.
Also when you grow with a lot of fat people around you you don't even know how normal weight looks. I noticed this last time in Paris. I had completely forgotten how normal weight looks.
It's worse even than that. Over 40% of people in France are overweight now - the numbers have increased rapidly over the past 20-30 years.
Paris is leaner than the French average, but you were probably still seeing a population with a fair amount of overweight people. Just, less overweight than what you're used to.
Seeing Paris 110 years ago would be a shock. (On many levels, but certainly on the average body composition level).
I have a book by Georges Hebert, who was an influential fitness instructor in France about 100 years ago. In it, he has pictures of French peasants shirtless, and some African tribesmen and women. They are in a form that today would be considered "unrealistic".
I can't find any of the peasant pictures online, but here are a couple of examples of the Africans:
Also when you grow with a lot of fat people around you you don't even know how normal weight looks. I noticed this last time in Paris. I had completely forgotten how normal weight looks.