The officers noticed the boy near the town of Weener in the Eastern Friesland region, just across the border from the Netherlands, they said.
Through questioning they discovered he was on his way home from the neighbouring country after taking a trip without his mother's consent.
The young man, who lives near Bremen, was also in possession of marijuana. When police also found some €1,850 in one of his pockets, the boy told the officers that it was “allowance money.”
The officers, based in Bad Bentheim, then called his mother, who explained that the money had gone missing.