One possible German company that was entangled with Sierra IP rights might be the former Deep Silver (Koch Media), because of THQ? Deep Silver bought a lot of IP assets from THQ including possibly some portion of Relic Entertainment's IP, which was a Sierra published studio. Though that German company no longer exists as such, because Deep Silver was recently purchased by THQ Nordic reuniting more of the THQ IP in Scandinavia.
But also, that doesn't hold a lot of water, potentially, because it seems like Gearbox bought Relic's IP in the THQ bankruptcy, not Deep Silver.
Though all of the above does help illustrate why game IP rights are so complicated and byzantine and a lot of classics are languishing because no one properly understands who has the real IP rights.
(The "NOLF Paradox" as some of us call it these days. Which I just realize is funny because Sierra was the original NOLF co-publisher, too.)