The service was evacuated following the stoppage at about 17:30 BST, with those on board transferred to a rescue train.
Eurotunnel spokesman John Keefe said between 400 and 500 people were affected after a "technical incident" forced the train to stop mid-tunnel.
The rescue train had to first travel back to Calais before going to the UK.
The failed train was towed back to Folkestone with the passengers' cars and belongings on board.
Eurotunnel said at 23:25 that "all trains have now arrived" and apologised for the delays..
Passenger Aggie Anim told BBC South East that after the train stopped "it was very hot, and we were all concerned about the oxygen".
She later tweeted: "The emergency train is moving!! People cheering... But wait we are heading back to France?! Booo Eurotunnel stuck."
She said staff on board the broken down train had been "very friendly and communicative".
In a statement on its website, Eurotunnel said services were currently operating with some timetable disruption.
It said there was a waiting time of about two hours at its terminals in Calais and Folkestone.
Hundreds of Eurotunnel passengers were stuck inside the Channel Tunnel when a train travelling from Calais to Folkestone broke down.