Rail traffic on Line A of the RER regional rail network stopped at 8.48am on Tuesday after a train broke an overhead cable, dragging it for a kilometre and cutting off the power supply.
Eight trains were stranded and evacuated with hundreds of passengers forced to walk to the nearest station.
While electricity was partially restored at 1.00pm, normal service to the airport was not expected to resume until Wednesday morning, officials said.
Buses were laid on to carry passengers to the airport and the nearby exhibition centre and in the evening the SNCF rail company announced the loan of two TGV high-speed trains to transport them.
Road transport restriction extended
The accident came as commuters were advised to take public transport, which was free, because of high pollution levels leading to restrictions on traffic in the capital and 22 surrounding towns.
Officials announced on Tuesday evening that only cars with odd-number registration would be allowed on the roads on Wednesday, following a ban on even number plates on Tuesday, because pollution remained high.
The RER B is Europe's second busiest rail line and, despite a major maintenance programme between 2007 and 2013, suffers regular disruption.Traffic was halted for four hours on 22 November because an overhead cable was broken.
Europe's busiest line
Europe's busiest line, the RER A line that runs between the east and the west of the region and carries 1.2 million passengers every day, also suffered serious delays on Tuesday, due to "various incidents" including a passenger being taken ill and signal malfunctions.
There were also delays on a line on the Transilien network because of someone died on the rails at Paris's Saint Lazare station.