Baku City Circuit was home to the 2016 European Formula 1 Grand Prix. This track is a conversion from the rFactor2 track created by dix-racing.pl. The track is accurate with the exception of any height changes in the western most portion of the track.
dix-racing.pl has given me written permission for the conversion and distribution of this track.
1) Unzip the archive
2) copy the baku_16 folder to your "steam\steamapps\common\assettocorsa\content\tracks" folder