The French call these markers bornes kilometriques . We know them as kilometer-stones or milestones.
Milestones show the number of the route as well as the distance to the next town.
Their red or yellow color also shows whether the route is a national highway or a local road. As a driver, you must follow the rules of the road. You must stop when the light is red. You must obey speed limit signs. If you get a flat tire, you must use a spare.