Can anyone tell what kind of berry/currant this is?
I am pretty sure this is a species of Ribes (Grossulariaceae, vernacular Finnish: herukat), and that it is not native to Finland. 

I would guess that it might be a variety of R. rubrum L., but it also might be a species unrecorded in Finland so far. You might consider sending the photo to someone at Helsinki Botanical Garden, or at the Natural History Museum. (If you got a twitter account, you might just sent the link to this page to @Raino_Lampinen and ask on his opinion.)