First off, the Peacekeepers didn't always look quite so much like Stormtroopers. In the first *Hunger Games* film, their helmets didn't encase their whole heads nor have those one-way visors of black glass:

[![picture 1][1]][1]
[![picture 2][2]][2]

I found [an article](http://www.zimbio.com/Screen+News/articles/7TJSx1LPv_v/Check+Out+Changes+Made+Peacekeeper+Uniforms) containing a statement from the designer Trish Somerville, who says she was "inspired by insects, particularly the praying mantis", but makes **no mention of the Star Wars Stormtroopers**. It is sourced to [this article](http://capitolcouture.pn/post/65379169338/exclusive-the-peacekeepers-uniforms-panems-new), which is written in-universe ("Summerville, who often collaborates with Cinna and other local designers, was asked by President Snow to take a more menacing direction with the look of the law"), but this doesn't necessarily mean they wouldn't include a reference to the real-life *Star Wars* films, as they do mention the Royal Canadian Mounties and Italian Carabineri. Panem is supposed to be set in our own future, after all. Who knows, maybe some 20th-21st century films will still be remembered in those far-off days.

The insect inspiration is backed up by [this interview](http://www.ew.com/article/2013/08/05/the-hunger-games-catching-fire-costume-qa-with-trish-summerville) (thanks @Richard for the find!), where Summerville says:

> I love the Peacekeepers that I did. I wanted to make them look a little more menacing, kind of insect-like. I draw a lot in my inspiration boards from different projects, a lot from nature, and animals, and insects. I just think that there’s so much there, in silhouettes and colors. The colors, they’re amazing, when you look in the insect world, and at in animals and nature. I wanted to make these Peacekeepers… after the first film, I felt like they needed to be bumped up a bit, because of what was going on in the second film with the rebellion that’s starting. I felt that we needed to show a transition, that the Capitol is stepping up its forces and making it much more intimidating and fearsome. So I went for this sort of spiny, praying mantis sort of look for them.

  [1]: https://i.sstatic.net/HAnSim.jpg
  [2]: https://i.sstatic.net/3Id2sm.jpg