I'm an American living in France, raising my child here. The two big things the French get wrong (that the 50's got wrong) that outweigh everything else they get right are:
1. Corporal Punishment. The French beat their children. Innumerable studies have been done and the results are remarkable consistent: Don't do it. Don't spank. Don't hit. In the 50's it was acceptable to hit your wife and kids. Let's not turn the clock back on that. Please.
2. Children should be seen, not heard. Like in the 50's, the French don't interact much with their kids. This is a terrible mistake. Yes, kids need some alone time -- that's a cop out. They'll make it clear when they do. The big mistake was that we started thinking that good parenting was karate classes and doing puppet shows, but this is like baking cookies: fine occasionally, but don't over do it. Take time with your child, let them direct their play, mainly watch. This is huge for them and one of the best things you can do as a parent. See your child. Understand your child. Be there for your child.