A variation first appeared on 4chan on January 13th in response to a picture of white girls sitting on the shoulders of black men in a pool. In early 2017, 'Hans, Get ze Flammenwerfer' became a popular comment meme on 9GAG left on stories or images the poster found particularly heinous.
In over three years, the post had gotten around 729 upvotes. On October 6th, 2011, a Reddit user VikingSlayer posted an image macro depicting an American soldier mounting a M2 Browning machine gun, pointing out how the way things are described appears in the eyes of a person who knows German language. On December 3rd, 2009, it appeared in a thread about the then-upcoming second season of the anime series Strike Witches on 4chan /a/ (anime and manga) board.
The original 4chan post was soon turned into an image macro based on a World War II-era photograph of a German Wehrmacht soldier with a flamethrower, which has been also (pictured below).