One man has even been jailed for eight years for multiple child abuse of his two daughters and other girls, evidence of which was collected online.
Detectives kept their work secret until now in order to get as much information on as many people as possible, the Süddeutsche Zeitung reported.
The massive operation was sparked by the appearance of two child abuse films being posted as pornography on an internet platform in the Constance region. The decisive tip came from Italy, detectives said on Friday.
The videos showed a ten- and 12-year-old girl being severely sexually abused. Within a month this video had been downloaded 48,000 times. The internet address was spread around various online communities and forums, detectives said.
Around 7,500 internet connections were thought to be in Germany, but only 987 suspects could be identified.
The rest of the downloads were in other countries where authorities have also been working on the case. So far 80 investigations have been started in Austria, 65 in Poland, 53 in Turkey and 38 in Australia.