Originally Posted by Robf
That won't be a problem in Hungary, but Germany and France are in between us, and I don't think documents from Hungary will work there.
But once inside Hungary, that sounds good
This is an international document, printed in French and Hungarian.
If you have all of the documents (letter of invitation, registration confirmation, this Hungarian pass) you will not have any problem. And by the way: there is no custom within the EU.