Toll roads in Portugal are mainly free-flow (no barrier) so you must fit your tag correctly so it can be read when you drive under the overhead gantry.
Please check here for fitting instructions.
Please click here for further information.
There is a clean air scheme for all cars driving in Paris and other French cities (the situation is changing so check the French government website below). You will need to display an emissions sticker showing the age and cleanliness of your vehicle. If your vehicle does not display the sticker, you could face hefty on the spot fines. The anti-pollution sticker can only be ordered on-line from the official Crit’ Air website : https://www.certificat-air.gouv.fr