...I didn't ask how much they are worth (by the way: more than 1 euro each...

), I just wanted to find out how rare these games are.
Games are always worth as much as someone wants to pay for it.
The gray label Obelix isn't listed in the PAL database, also it is not listed in the AtariAge database. I only found it on Atarimania.
The Xonox Sir Lancelot/Robin Hood is listed on Atarimania in PAL, but not here on AtariAge or in the PAL database.
Most Xonox double enders aren't really rare in germany, there are always some for sale on ebay or other platforms.
So I count 4-5 for the Obelix and 2-3 for the Sir Lancelot/Robin Hood.
BTW: The next Retro Börse is in Bochum, right?