Who controls katniss? How do they show this? How does katniss go against them?

Katniss and others are controlled by the state;

Who has the power?

Well, the main source of power in The Hunger Games is clear: the totalitarian government of the Capitol. Because the Capitol holds most of the country of Panem’s wealth, the government there is able to control the people in all of the districts across Panem. The Hunger Games, then, are the ultimate display of the government’s power and were designed to warn the populace against rebellion. In the Hunger Games, the citizens of Panem become nothing more than pawns in an elaborate game of life or death. Since only one teenage contestant, or "tribute," can win, the tributes are forced to kill teens from the other districts and one from their own district. It's all symbolic of how the Capitol prevents the people in the districts from joining forces and rebelling – the Games keep the people of the districts divided and fighting among themselves. Worst of all, the government broadcasts the event live on television, reinforcing the idea that the tributes are giving their lives for little more than the entertainment of the Capitol.

Let’s not forget, though, that this book is also about ways to resist the kind of power that the Capitol represents. While the people of Panem might not have the Capitol’s money, they do have other ways of fighting back. Remember when District 12 gives Katniss their salute? Or when Katniss covers Rue’s dead body in flowers? These symbolic gestures call attention to the fact that there are actual people in the Hunger Games – real live humans, not just game pieces. In that sense, these small moments of defiance can be very powerful.

Really nobody controls Katniss, that is what makes her such a strong female character. The Game makers and President Snow think they can control her. They change the rules of the competition as it is being played out. Katniss, however, knows how to defy these people on camera. She threatens to pull a Romeo and Juliet with Peeta and the poisonous berries. They back down.