The sign you are referring to is the "Camper van site" sign. This sign indicates that there is a designated area where campers or camper vans are allowed to park and set up for overnight stays or rest.

According to German traffic laws, this sign is used to guide drivers of camper vans and motorhomes to appropriate parking areas that are equipped for their needs. These areas often have facilities such as waste disposal, water supply, and sometimes even electrical hook-ups.

It's important for drivers to adhere to the regulations associated with such sites, which may include restrictions on the length of stay or additional fees. Parking in these designated areas is generally safer and more suitable for larger vehicles like camper vans.

If you have any further questions about camper van regulations or other traffic rules, feel free to ask!