The platform, dubbed ‘Boystown’, was shut down after police arrested three site administrators and one active user, who allegedly uploaded more than 3,500 posts to the site.
Prosecutors in Frankfurt and Germany’s Federal Criminal Police Office said the three German administrators, aged 40, 49, 58, were arrested in mid-April.
One of the three suspects was arrested in Paraguay and Germany has since requested the extradition of the man.
The names of the men have not been shared in line with Germany privacy regulations.
But the group had been helping pedophiles spread child pornography, including “images of most severe sexual abuse of toddlers”, prosecutors say.
They also gave advice to members on how to evade law enforcement when using the platform.
The bust came after a multinational investigation involving Europol, the Netherlands, Sweden, Australia, the US, and Canada.
The team had previously searched seven buildings in connection with the porn ring in mid-April in Germany before nailing some of the men.
Authorities described the platform as “one of the world’s biggest child pornography darknet platforms” and had been active at least since 2019.
“The platform had several forums and chats — the illegal pictures and videos were kept in the forums; in the chats, the members could communicate,” prosecutor Julia Bussweiler told Associated Press.
“There were several language channels to facilitate the communication,” she added.