It is interesting to see what French kids have on the menu at their schools. Here is a link that will show you the weekly menu in a random school somewhere in France. You can click on translate to see the page in English. The translation is reasonably good.
As you can see, every day’s menu is, it at least a three-course menu. It shows variety and it is rather well-balanced. As a side note, it is also interesting to know that meals are free, as schools are in France, as they are the school of the French Republic. No lunch money needed.