Some one might be selling a replica or something, though the accuracy of such products varies.
Let’s see… Google: Katniss Knife… yup. Though some of those are not like the knife you want, at all. Here’s a good still photo: http://vignette2.wikia.nocookie.net/thehungergames/images/5/5d/Katniss_knife.jpg
Here are the stunt props. http://www.ronmendell.com/RonMendell/Images/Hunger_Games/Stunt_props.jpg I get the feeling these may have been custom made for the film.
Here is someone asking your question on a knife cough maniac cough enthusiast forum: http://knifeforums.com/forums/showtopic.php?tid/921529/
They confirm it is a prop fantasy knife. They say it doesn’t have a real edge and has a piece of chrome tape on the side to make it look like it does.
However, there are plenty of knives out there to look at. Googling “combat knife saw” brings up some related designs. The term “knife/saw combo” applies. Note that the saw may look cool, but doesn’t improve the design for combat purposes unless you happen to need a saw, like to cut the branch on a bees nest that happens to be right over a sleeping target’s head…