When Ana Maria Bittencourt Marques, a 45-year-old nursing assistant from Brazil, boarded her plane at Paris's Charles De Gaulle airport, she was expecting to touch down in the Danish capital, where she was going for a holiday.
So she was surprised to find Greek lettering at the airport when she landed and even more surprised to learn that she was in Athens.
Marques had been given a boarding pass in the name of another passenger on the Greek flight, Marie-Christine Midavaine.
She says she did not notice the mistake because she was in a hurry and nor did an Air France agent at the departure gate notice that the name on her passport was different to the one on her ticket.
She snoozed during the flight and first became aware that something was wrong when she saw Greek letters at Athens airport.
Air France flew her to Copenhagen through a connecting flight in Luxembourg.
The airline says that passenger safety was not compromised but has launched an internal investigation into the incident.