The records indicate that several major publishers, either directly or through subsidiaries/secondary parties, have been sending out letters to German citizens requesting varying levels of payment in return for not being sued. Where things get murky, however, is how the publishers are seeking out the accused pirates, using not always reliable "IP address-only evidence" -- easily circumvented with proxy domains and such. You know, hacker stuff.
TorrentFreak's report indicates that a variety of publishers and distributors are involved, including (but not limited to): Atari, Koch Media (representing Techland's Dead Island and Prison Break, and Eidos/Square Enix's Deus Ex: Human Revolution as well as Dungeon Siege 3 and various Final Fantasy titles), Daedalic Entertainment (representing LucasArts), Codemasters, BitComposer, Ubisoft, Kalypso Media, dtp entertainment, and Aerosoft. It is currently unclear how many settlement notices have been sent out by each company, or if any will continue doing so after these actions have been brought to light.
Witcher 2 developer CD Projekt Red was recently pursuing similar cases in Germany until it announced the end of the practice last week.