In this part of provincial France, which is doubtless a world away from Bonsoir's, there are all sorts of shapes around.
But on the whole, while we are blithely generalising, people are definitely slimmer than in the UK. I've been overseas for 17yrs and in that time I have seen the population in the UK slowly grow fatter. Exchange students from the UK are recognisable on my campus here because they are generally heftier all round than their local counterparts, with chunkier hips, bums, tummies, etc., and a tendency to wear clothes that highlight those areas rather than concealing them. The Germans are also identifiable, but it's not because they are fatter, merely in their dress, stature, etc.
The women I work with are almost all slim. From what I see, they eat balanced meals, do not snack and seem happy and reasonable in their approach to diet. No one seems to be starving themselves. Some smoke, but no more than one cigarette after lunch.
Portion sizes are far more reasonable here. Meals are generally well-balanced. School meal menus are varied, and offer no choices: it's take it or leave it. DS1's menu for Monday is Grapefruit/ Turkey à la moutarde with carrot purée/Yoghurt.
Far fewer people eat in the street than in the UK, and those who do (generalisation alert) often belong to the socio-economic groups that are hardest hit by obesity here.
During pregnancy, weight and diet are closely monitored, and the idea that you'd inevitably be fatter after having kids isn't one I've come across here.
The only two women in my department whom I'd say were alarmingly skinny, with obvious anorexic tendencies, are both from the UK. My French colleagues look pretty good, really.
One thing that has not been mentioned on this thread, I think, is that French men are also, on the whole, slimmer than British men. It is a general thing, not merely linked to neurotic tendencies in French females (though those do exist, obviously, in some women).
Cartons of vegetables have yet to reach the wilds of PACA, though. I'm not sure what that's all about. Where do you buy cartons of veg?