In “Pays Imaginaire,” the French electro-pop duo Polo & Pan paint a sunny, pristine, imaginary world where everything is bounteous and everybody is happy. People can fly; there are banquets of blueberries and wine; things seem to sparkle. An optimistic series of open chords embody that sense of no-worries perfection, and the end result is like if LCD Soundsystem reinterpreted Debussy’s Clair de Lune (and indeed, the band lists these two as their main influences): romantic, robust, and dreamily charged. But, as we learn at the song’s end, it was all just a dream.