I also pressed on the part where the german dude stuck the paper and now the power button works again.
My phone fell on the ground, when I pressed that part of the phone I could feel something click or snap back in and the power button works again.
It is also possible to start this phone without the power button. Hold the volume down and home button while connecting it to an USB port of a computer ( I needed somebody else for that)
The phone will start in download mode, but if you press volume down once more it reboots and it starts!