The Federal Criminal Police Office reported that investigators searched the apartment of a 20-year-suspect from central Hesse state on 6 January and detained him.
"The prosecutor's office in Frankfurt, the Central Office for Fighting Internet and Computer Crime and the Federal Police Office (BKA) searched the apartment of a 20-year-old suspect on January 6 and took him into custody", the BKA said in a statement.
According to the Federal Police Office, the arrested man acted alone, he said his motivation was anger over public statements made by the affected politicians and journalists.
AP reported, citing authorities, that almost 1,000 people were affected by the data breach. In most cases, the reports say, the information that went public was narrowed to basic contact details, but in up to 60 cases more extensive personal data was distributed.
The data was first published before Christmas via a Twitter account that was reportedly taken offline on 4 January.