Whenever I see posts like this I want to grab people and take them to my local supermarket. There you will see people of all sizes wearing all manner of clothes. Very few of them are what could be described as chic.
Paris is a different world but most of France is rural and definitely not chic.
It may well be that your local intermarché is poorly dressed, but broadly it looks like the average French city lady looks smarter and chicer and generally following some unwritten rules, compared to average British city dweller. Many thanks to Atalune, have found those threads !