A very old thread that was revived so the little round sticker still raises questions; so FYI (and feel free to provide additional information):
The sticker -with changing colours per year I suspect- is for German regulations regarding gas installations (a biennial G607 gas inspection) and since the California is German and there is a gas installation on board from new, it has this sticker on it. This rule does not apply outside Germany and some other countries such as Switzerland and Austria.
A valid inspection can be verified at German campsites +Switzerland & Austria (
and is necessary for their car insurance). If this is the case, they will most likely check the Germans, but I have read several times that foreigners were also checked and denied access to the campsite. I have not experienced it myself, but have only visited Germany and rarely at campsites.
For your own safety, it is of course best to have your gas installation checked after a while. In Belgium you can do it at certain camper distributors. There is/ are even a Belgian camper dealer(s) who can/may carry out the tests and are compliant for the relevant countries; that dealer sticks such a sticker on it (and makes a logbook and certificate). There are also several in the Netherlands who do it this way. How it works for you (UK, other countries) I don’t know but I think you can have your camper gas installation checked and receive paper proof. The sticker itself is only available in Germany and cannot be extended with the same type of sticker (with new date) for all others unless you go over there (or have it checked by those with a ‘German gas inspection G607 patent’). Therefore I assume that the sticker can be removed for us and that paper proof of inspection of the gas installation is/ might be sufficient. But there is a possibility that access to a campsite will be refused. If so, I'll find another place.
I'll keep the sticker for now and when the date on it is expired, I'll remove it because having an expired date at the back is also quite unnecessary, I think. Unless by then it becomes an European regulation
Extra info:
1: This inspection (DVGW G607) includes a check of the tightness of the entire gas system using a pressure pump, a check of the operation of the appliances, a test of the thermocouples on the appliances and a check of the condition of the technical parts such as regulators and hoses ( corrosion, fractures, fastening, etc).
2: In Germany, the G607 inspection is no longer a requirement to pass the general car inspection, where this was previously the case. The intention is to introduce a new arrangement in mid-2024, but I will leave it to the German members to explain this in detail. Simply put: It remains for them necessary for campsites and insurance, but no longer for car inspections.