It's stretching the imagination a bit to think that the OP really thought that ALL British children were noisier, fatter, whatever than French children.
The OP is a grandmother to British children as are most of us here.
Lots of sweeping statements are made in relation to behaviour, habits, etc., and people pick up on this but it's surely not against the rules?
Many a time posters say how in Mediterranean countries very young children are out late at night with their parents, in restaurants at midnight, fall asleep where they drop, etc.
In the main, British children go to bed much earlier.
Both sweeping statements but not really saying that one style of parenting is better than other purely based on nationality.