"It's funny because it's true". Parts of the German green movement (esp. the anti-nuclears) were actively funded by the KGB.

Any proof for this claim?

What are you talking about? Greens are neither pro-gas nor pro-Russia. They were amongst those warning previous governments of energy dependence on Russia, and were basically the most decisively pro-Ukranian party in the previous government. They also weren't the ones who made the decision to shut down the remaining nuclear plants, despite what "conservatives" would like you to believe.