It's hard to know what advice to give for European travel, having never been there or researched it. However, I read a tip from an experienced stealth camper that in the States, it's good to ask the fire department for good inconspicuous camping spots. Take with a grain of salt. Is that a recognized saying in other countries? In other words, don't be overly trusting of this advice. It might not work very well, but try it out if you're inclined to.