If you live in Paris, you'll be familiar with the sight of people jumping the barriers to get a free ride on the Metro and RER.
In fact, it's probably almost as common as spotting someone actually using their ticket or Navigo pass to get through the gates.
But the huge scale of the problem was revealed on Wednesday as an operation to crack down on ticket cheats got underway.
All in all a staggering 1,500 fare dodgers were snared within just three hours.
From 2pm, around 500 agents (a group made of ticket inspectors, SNCF and RER security officers and plain-clothes policeman) got into position at all the entrances to the train lines at Gare du Nord, stopping each passenger and asking to see their tickets.
Not surprisingly, many of those stopped were unable to produce a ticket and the numbers soon clocked up to 1,500.
“I lost my Navigo pass four months ago and I don't want to pay €60 to get a new one,” was one woman's excuse, according to Le Parisien. She described the operation as “frankly excessive”.
The operation aimed to send a strong message to regular dodgers, estimated to make up 7 percent of all passengers, who may have calculated that it is worth their while to risk occasional fines rather than pay for a Navigo public transport pass.
Thanks to the 1,571 cheats who were caught transport officials raked in €12,000 in on-the-spot fines, with the operation set to be repeated on Thursday and Friday afternoons.
Fare dodgers were handed on-the-spot fines of €30 for a non-validated ticket and €50 if they had no ticket at all. An additional €30 is added if the fine is not paid immediately - however, however that requires the inspectors to get the correct identity of those responsible, which is not always an easy task.
However, the foiled attack on a Thalys train last year led to a change in law, giving increased powers to SNCF security agents, including the authority to search travellers' luggage and to hold them until transport police arrive should they refuse to declare their identity.
In February 2015, SNCF reported that it lost €500 million every year through people trying to cheat the ticket system, and increased passenger fines by up to twofold, penalizing passengers according to the length of their journey.