I agree Whitebeam, I have one in the garden.
I disagree on both whitebeam and more general sorbus.
Elm of some sort could be possible, the picture quality makes it hard to tell, but the green fruit do not look like elm, or hornbeam.
Tengu, its a bad photo (not one leaf shown flat and deep shadows, and you don't show but a hint of the fruit) and you could have helped with additional details, like where in the country you found it, and what sort of place it was growing.
That said, I am going to say I think its an
Alder. Those fruit look classic alder, and what can be seen of the leaf shape and order of budding off the twig could be right too.
Why it isn't a whitebeam:
The leaves in Tengu's photo are longer relative to their width than Whitebeam (no sign of the white underside), and more important, look at how the whitebeam leaves sprout from their twigs, three or four all come out together. Now look at Tengu's picture, the leaves very clearly come off alternating about every 20mm.