There are 6 different categories for the Crit'Air vignettes. This all depends on the emission of your car. Each city will determine what the rules, or levels of emission, are. Paris is the first city, within the Paris ring road (périphérique), to introduce an eco-zone. It's, therefore, important to advise your drivers to apply for a vignette when driving in or through France. This way they will avoid penalties.