I took photos of the newly opening leaves on my Horse Chestnut tree today, they are pretty much like yours. It's a huge tree.
I found a seedling which has leaves about 2 inches long, they look the same but smaller. The smaller plant in your pic doesn't have the drooping leaves like a seedling has when opening, they might have come from the roots.
It's late here, tomorrow if I download my photos I'll post some pics.
