La Provence newspaper reported that while passengers relaxed on a high-speed TGV train on Saturday evening, the two-metre snake managed to escape from the bag it was being carried in.
The snake's owner noticed the serpent had gone missing and alerted the train's guard.
He decided to wait until the passengers had all left the train at Marseille's Saint-Charles station. Once the train had emptied, specially trained firefighters boarded the train to find the snake.
They dismantled sections of the train's walls and managed to find the crafty escapee in a ventilation shaft.
The slippery serpent was returned to the bag where another snake was also being transported but had decided not to move.