The 27-year-old Chinese father of two, who was travelling with his wife and children, reported to the Autobahn police station near Wiesbaden that his wallet had been stolen on Friday, police said in a statement.
While giving the officers details, he admitted that he couldn't rule out having lost the valuables at a petrol station that afternoon.
But at the very same time, a 48-year-old taxi driver appeared at the police station in Frankfurt's Sachsenhausen district to hand in a wallet containing over €14,000.
Police were quick to put two and two together and realised that the wallet was the one belonging to the Chinese family.
In fact, the news travelled so quickly that the couple and their children hadn't even left the police station by the Autobahn by the time the wallet was identified.
As it turned out, the father had left the wallet on the roof of his car in a moment of forgetfulness while taking a coffee break at a service station near Wiesbaden.
When he drove off to visit a friend in Frankfurt, it slipped off the roof and onto the roadside, where it was later found by the taxi driver.
Thanks to his honesty, the whole family were able to continue their visit in Germany – and pay for their tickets back to China.
The family left behind €500 as a thank-you to their serendipitous saviour.