At 2:30 p.m. on May 2, the passenger took a taxi from the Temple of Literature to Vietnam Women's Museum, both popular tourist destinations in Hanoi, in a 2.5-kilometer journey for which the normal fare is around VND40,000.
However, the driver deliberately used a longer route and charged him VND200,000 based on the meter fare.
After paying the money to the driver, the German passenger took a photo of the taxi number plate and informed the Hanoi Tourist Information Center who asked local authorities to investigate the incident.
Transport inspectors stepped in and tracked down the driver, who was found driving the taxi without a license.
At a meeting with transport inspectors Thursday, the driver admitted his mistake and returned the money that he had overcharged.
The cheating of foreign tourists has been a problem in Vietnam for some time, affecting its reputation as a safe and friendly tourism destination.
Taxi scams used to be common in Vietnam, but rising competition in the transport sector has helped stem the problem. However, foreigners are still regular targets.