My German is quite rusty.

https://www.tagesspiegel.de/politik/moegliches-engagement-von-altkanzler-schroeder-welche-rolle-rosneft-im-russischen-machtgefuege-spielt/20255236.html

Putin's last station during communism was the KGB officer in Dresden in the DDR. This makes his contact with Merkel a distinct possibility. He further helped the Dresdener bank maintain links to St. Petersburg.

Sechin was the president of the KGB Youth in Leningrad.

It states that Schröder is a close, personal friend of President Putin and that this has facilitated the Rosneft pipeline project.

After the Russian intervention in Ukraine, Setchin remained off the US/UK sanctions list and while Putin was on it. This enabled Setchin to bypass the sanctions for the Rosneft project.