Raids were carried out in ten of Germany’s 16 states, including 20 addresses in Berlin, the BZ newspaper reported. One hundred officers were involved in the Berlin operation which was initiated by the public prosecutor in Frankfurt am Main.
Three of the five men arrested were from Berlin, aged 37, 46 and 49.
A 49-year-old from North Rhine-Westphalia and a 47-year-old from Lower Saxony were also arrested.
The investigation centred on the users of an internet forum. The probe focused on those looking at child abuse images and those abusing children.
The 550 police officers seized 260 computers, 850 external storage hard drives, 150 mobile phones and tablets and 7,500 CDs and DVDs.