Germany is virtually the sole power keeping the EU from collapsing on itself economically geographically and politically, even if France is the one with the nuclear arsenal.

The US has thousands of US soldiers in EU NATO states, do you think US will just sit there and talk about financial sanctions while Putin kills US troops in Europe?

By the way Germany also has nukes, not their own ones, but they are not just there for fun.

While there are nukes in Germany, they're not Germany's nukes unless Germany can determine when/where said nukes are used. (The ability to stop the US from using them is not enough.)

If Russia uses nuclear weapons first in a European war then yes. But the targets would probably be Russian forces in or approaching Poland or Germany rather than mainland Russia itself.