The 41-year-old tourist from North Rhine-Westphalia was on a bike ride with her husband when the incident happened.
The pair were crossing a field near the town of Gadebusch when they unknowingly entered the path of a boar hunt.
Suddenly, the woman felt a pain in her chest.
Looking down, she saw that she had been hit by a rebounded shot – but the underwire of her bra had deflected the blow.
The woman came away with just a bruise.
The woman's husband spotted the alleged shooter in the next field and immediately approached him to explain him what had happened.
"Those in charge of the hunt then broke it up straight away," said police spokesperson André Falke.
Gadebusch Criminal Commision is investigating the incident on suspicion of injury caused by negligence.