Soni, schaplin, Art and Steve, thanks for your nice words!
I have no clue what variety it could be, but the main thing is, it is a true keeper for me.
Btw: Thank you to my friend Phil from northern Ohio (peak42),for explaining a non native english speaking kraut the word "keeper". :-)
Now i can use it myself! ;-)
Very distinctive is, like Steve mentioned right, the very light grey stem.
Also the very little lobed leaves, which stay kind of small compared to other figtrees.
They appear to be dark green, leathery thick, and shiny...
No other variety i own comes close to that.
I think not to know exactly every tree you own can make it even more exciting.