A 15-year-old boy drowned in the Achterdieksee in Bremen on Monday evening.
He drowned in the water, said a police spokesman on Monday.
The boy was then taken out of the lake, but could not be reanimated by the emergency services, as reported by several media.
The young person died at the scene of the accident.
The first reports said it was a 13-year-old.
The police have since corrected that.
According to a spokeswoman for the police press office on Tuesday morning, many onlookers were there and observed the incident.
A rescue helicopter was also used.
The spokeswoman did not initially provide any further details.
kha / dpa