This sounds like a dangerous (politically and physically) opportunity to have a demo in conjunction with the NF and their like.

I checked out the ZedFed (see link) and it does look like a dodgy "my country, right or wrong" kind of set-up, well deserving of having it's conference disrupted.
Although it would be fun to eg. lock their musical entertainment in a back room and put a samba or perhaps punk band on unexpectedly, the kind of people they are and the current political situation means that security will probably be aimed at preventing serious hassle from the far right / arabs / islamicists and so on - and as a result may be difficult to do a decent demo.