In France, when you enter a town/city or even the tiniest of hamlets, first, you have to reduce your speed (that's a given) but you also have to be careful with cars coming from your right as they often have the right of way (unless they have a stop sign). This is the so-called "priorité à droite". Since it's not always obvious a street on your right side has a stop sign, caution is always needed.
Another thing to be aware about when travelling through a town is the so-called "ralentisseurs" which may take the form of 1) the universally recognized bump, also known as the "dos d'âne" (donkey's back), 2) an artificially created strong bend in the road ("chicane", also used in road racing for the exact same purpose), or 3) a plain old obstacle on your side of the road (which often allows for parking cars) that forces you to wait for traffic on the other side to go through (or, at the very least, slow down).
An other thing is, when you want to turn left at an intersection, and there's somebody in the opposite lane that wants to do the same thing, you should position yourself behind that car, unlike what is commonly done in the USA where you go right in front of the car.