About 700 people joined a demonstration against a "hard Brexit" departure from the European Union (EU).
The North East for Europe group said it wanted to "show solidarity with fellow EU citizens living in the North East" at the rally in Newcastle.
Spokesperson Carlos Conde Solares said they were "appealing to the middle ground, particularly those who voted Leave and now aren't sure".
The English Defence League (EDL) held a rival protest nearby.
Prime Minster Theresa May wants to trigger the Article 50 process by the end of March.
Mr Solares said it was "OK for people to change their minds, but it is important they don't leave it too late".
Pro-EU protestors gathered at Newcastle's Monument after a march from the City Pool.
The rally was addressed by a number of national campaigners, former MEPs, academics and a former European Commission official.
Margaret Edmondson, who voted to leave in the referendum, said the protestors should "just accept" the result.
"You know how an MP gets a very small majority - what if we said well, I didn't vote Labour, we'll have it again so Conservatives get in," she said.
Migration historian Tanja Bueltmann said she had come from Germany to "contribute to life and society in the UK and I think I've been doing that every single day since I arrived eight years ago".
"We're very much in limbo now and the fact that we've been used as bargaining chips, I find frankly very disgusting," she said.
Daniel Russell, who tutors refugees, travelled from Leeds to the rally because it was "important that people still make their voices heard about what's happening in the EU".