Decopunk is a recent subset of the punk sci-fi genres, centred around the Art Deco and Streamline Moderne art styles, and based around the period between the 20s and 50s.
In an interview at CoyoteCon, steampunk author Sara M. Harvey made the distinctions “…shinier than DieselPunk, more like DecoPunk.” and “DieselPunk is a gritty version of Steampunk set in the 1920s-1950s. The big war eras, specifically. DecoPunk is the sleek, shiny very Art Deco version; same time period, but everything is chrome!”
The term was also independently proposed for the movie Sky Captain and the World of Tomorrow and the video game BioShock.
Some examples of Decopunk
Red Hawks, art by Lipatov
Art by Brian k Robinson
Cityscape architecture art by Hugh Ferriss
At Home, art by lady deuce
Art by Yanick Dusseault
Art by Clockworkvirus