The 49-year-old woman was caught by police officers in the city of Aachen, North Rhine-Westphalia, on Monday near the Dutch border, after she had arrived from the Netherlands by car, according to a police report.
The officers at the border crossing asked the woman to open the trunk, and they then conducted a search inside the vehicle.
They found a brown paper bag from a fast food restaurant, which suspiciously didn't smell of food, but was still full.
The contents of the bag turned out not to be a meal – but it was a small package wrapped in adhesive tape. This contained a brownish substance that a quick test by police showed it to be heroin.
At the police office, the heroin was recorded as weighing 500g with an estimated black market value of €25,000.
The woman was arrested and reported to the police under the Narcotics Law in connection with the illegal import of a large quantity of drugs.
She was then handed over to the Essen Customs Investigation Office, based in Aachen. She was due to appear in court in Aachen on Tuesday.