Shanson is the Russian underworld and prison music.
The style owes a lot to French Chansons and to the Russian art music of the 19th century, as well as to tango and klezmer.
These are very popular, becuase at one point or another, a large segment of the Russian populatin has spent time behind bars, often for trivialities.

Taganka.
A love-hate ballad to the Taganka prison, one of the worst in the Russian Empire and Soviet Union, until Khrushchev tore it down.
www.youtube.com/watch?v=jFARFG4RYSQ

Here is a scene from the movie "Shtrafbat" about a penal battlaion in WW2. The penal battlaions were temporary formations made up of criminals, political undesirables and the disgraced. In the clip they found some moonshine and one of the Jews sings a shanson.
Here is a fuller version, slightly different.
www.nesueta.net/download/songs/raz_poshla_na_delo_berenson.mp3