If you are travelling to France via the Eurotunnel service from Folkestone then you will emerge from the Channel Tunnel at the Coquelles terminal in Calais. It is further inland than the ferry port and therefore has excellent road connections onto the Autoroute network.
It also located next to the Cite Europe shopping centre, popular with day trippers. The Coquelles terminal itself has a range of facilities including toilets and a petrol station.
For more information about Calais port click here.