Here's the download link:
speedy.sh/GGcDM/bloc42.rar
Unfortunately the map is not on workshop, as it is a custom version of bloc42 made by someone from ZARP, but you can trust me, no worries.
You must put the .bsp file into Steam\SteamApps\common\GarrysMod\garrysmod\maps
And the .ain file into Steam\SteamApps\common\GarrysMod\garrysmod\maps\graphs