The important point, in my opinion, is that these refineries have been under direct German state control for years now. They only belong to Rosneft on paper because nobody wanted to jump through all the hoops to disown them. That would lead to endless battles in court and would likely require payment by Germany to Rosneft, which can be avoided by simply putting them under administration, as is the case now.

This is the reason why these refineries are already exempt from similar sanctions by the UK.