The Berlin teen has been ordered to compensate the girl, who was 13 years old when she sent him the photos.
The pair attend the same high school and were in a relationship at the beginning of last year, reports Golem.
During the relationship, the boy – who was also 13 - asked his girlfriend to send him intimate photos on a regular basis, said the girl's lawyer Johannes von Rüden.
The 13-year-old complied – but rather than keeping these images to himself, the teen shared them with his friends via free messaging app WhatsApp.
The images soon spread around the school the pair attended.
In a hearing in January, the court awarded the young girl up to €1,000 in damages. But it was eventually agreed that the boy would pay €500 so long as he could prove that he had earned the money through his own work by the end of the year.
Young people don't realise the dangers
Ehssan Khazaeli, academic associate at law partnership Werdermann & von Rüden, who represented the victim, told The Local that this was the first time the firm had dealt with a case like this.
"Victims often shy away from confronting the situation," he said. "They report it to the police, but don't take the matter any further.
"However, this itself often makes a considerable impression on the perpetrator."
Reckless social media use among teens and young adults is becoming ever more of a problem, Khazaeli said.
"Young people don't seem to realise that pictures they send won't always stay with the recipient," he explained.
Particularly in schools, images can travel quickly through private messaging and WhatsApp, Khazaeli told The Local - meaning that even feature's like Facebook's "only for Friends" option is no guarantee that content won't be seen by many other people.
Teen will earn the money through part-time job
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"The spreading of these images, and the subsequent drastic effects on the young claimant's quality of life and development, demands financial compensation," said the judge.
The boy was fully aware of the potential consequences of his actions, the court ruled – and the spreading of the photos caused the girl considerable humiliation and embarrassment.
His actions had interfered with the girl's personal and sexual development, the judge ruled.
The teen will earn the money through a part-time job, reports Golem.
By Hannah Butler