Same thing in France (SACEM). The venue pays the fees, and it is dependent on the scale of the event, the entrance fees, etc... The DJ doesn't have to pay anything, he just plays the music the venue has paid for the right to play.

And it is essentially the same thing with Twitch here, as Twitch pays the necessary fees that allow the DJ to perform on their platform.

It may be different in some other countries indeed. I think in Germany, home of the infamous GEMA, DJs have to pay a fee in certain conditions, in addition to what the venue pays.