Probably ebay I guess, unless you have a mechanical engineering dealer close. It's hard to see exactly what you've got there, I think that's a milling head (whatever it is, it's complete anyway). Pressure gauge and piping, bore gauge, who knows what else is buried further down. you could be talking several hundred EUR. Maybe you can take some higher resolution photos and single out individual items other's can chime in too with identifications and estimates.
Worst case, you'd easily make your EUR 30 back!