Crit Air sticker for Paris trips

A quick reminder to anyone who is going via central Paris (or Lyon or Grenoble) this summer, that they will need a Crit'Air sticker to show the emissions class of their van.
I got mine for a trip to Paris over easter.  The process was fairly painless on this site (link).  Just needed to post a picture of my V5C and a payment of 5 Euro, and it came through the post 5 days later.
Given that Le Parisiens have a healthy disrespect for many of the local regulations, I was skeptical about the uptake/enforcement of this, but I can confirm that where we were (9th arrondissement) most of the vehicles were displaying one.
More info at RAC website.

Happy travels.

Many thanks for this useful information.