Found this actual footage of 70s pop duo TINNA performing a track from their 1979 album "Monday Morning Rain" so I decided to import the video here. I've already written about the title track here.
Not quite as grabbing as "Monday Morning Rain", "Paper Doll" wouldn't fall into the City Pop or AOR genres. I would probably go for New Music myself. It's a pretty stately ballad delivered with heart and harmony from Tomoko Soryo and Mariko Takahashi（惣領智子・高橋真理子）, and I think that I actually prefer the original recorded version because of the guitar and piano coming to the fore. Unfortunately, I couldn't track down who wrote and composed "Paper Doll", and no, it has no relation to the song by Tatsuro Yamashita（山下達郎）.