The NYPD has been using its big orange kettling nets to contain some demonstrators and control the crowd (others have been "fenced in by metal barriers"), and there are unconfirmed reports of police using pepper spray. It sounds like a tense scene, with protesters yelling at (random?) people in suits and generally testing the police. (Others are reportedly chanting the First Amendment.)
You can watch a live stream from what looks like the intersection of Broadway and Wall Street here. We'll keep you posted as the demonstration develops.