Same with blacks and Asians who do not see outsiders that often. They stare and make comments about what's different, what they are not accustomed to.
It is slightly different though, I've seen how the little kids in Africa act towards white people and they'll either ask blunt but not racist or rude questions like, "where do you come from?", "can we follow you?" and basically just act like they have an audience with Santa.
The worst thing you might hear (dunno if it's even bad) is a child just exclaim with a smile, "white man!" that's it. My mate went to small towns and villages around Asia and he said the kids did similar things to him and some randomly gave him gifts (usually broken toys or whatever they had to hand)
So it's a bit different to monkey chants (in the worse cases) and whispering, stares and finger pointing.
Hopefully before the Euros, Poland will have addressed this by maybe using some public service announcements or the likes. Get some celebrities involved and really try and address it head on.