Dessert is eaten with a spoon. No matter what is being served, the only acceptable implement is the spoon, no matter how maladapted to the task.
Ice cream? Spoon. Good choice.
Cake? Spoon. Many different utensils work well with cake; the French choose the spoon. (But working well with utensils is a feature of cakes, not any particular versatility on the part of the utensils.)
Blueberry tart with a really hard crust? Spoon. And be careful about bite-sized bits of crust suddenly shooting across the table. No, you may not have a knife. If you suspect that a hard-crust tart is in the offing, discretely hide your cheese knife under a napkin or somewhere in order to remain properly armed.
Bunch of grapes? Spoon. Alright, most people do in fact leave the spoon on the table to eat their grapes. But you still get one.
Coffee. Coffee is served in demitasse cups. A single mug of coffee the size that certain friends of mine have for breakfast in the States, or a Grande at Starbucks, is enough to fill a half dozen of these little jokes. Mind you, there may be about the same amount of ground coffee involved in making these various cups - the french version is just squeezed into the smallest possible volume.
Another of the myriad coffee rules is that coffee at the end of dinner cannot be served with dessert. Verboten. I've been to some restaurants where, if you say so very clearly when ordering dessert that you want your coffee at the same time, they'll shake their heads in dismay over the sad American and serve it the way you want. But that's exceptional. Most places, even if you order coffee with dessert, they will serve your lemon tart with its spoon and bedrock crust, make the coffee, keep it there behind the counter until you have finished every last crumb of your tart, and then serve the now-cold coffee. If you try to trick them by pushing your tart to the side in the hopes they will bring your coffee after all, they will either not do it, or they'll forcibly take your tart away (often by scooping up the plate and placing it in a stack of used dishes such that you don't really want it back after all; if there's the whole table to clear they just do it by stacking your friend's dessert plate on top of yours), before setting down the coffee. You are in a dessert phase, or a coffee phase, but never both. You may keep your glass of wine come what may.
Beer. Beer shalt not be taken with a meal. No. You may have a beer, and you may have dinner, but a beer with dinner is just not done. Not even with sausages and fries, or pizza. Finish your beer and turn to a nice glass of wine with your meal.
The beer for dinner thing reminds me of being asked a few years ago if it was ok for teenagers to have a glass of wine at a restaurant dinner. Yes, young people are included in wine-drinking as part of the family dining experience, and that extends to restaurants (though you don't see many youngsters actually imbibing). In fact, I couldn't think of what the drinking age was in France. Turns out, there wasn't one. Any person of any age could purchase the alcoholic beverage of his or her choice at any supermarket. It's just that kids don't, usually, at least until recently. Just this year they passed a law saying you have to be at least 16 to buy booze.
That's enough on food. On to more serious issues. Maybe.