What license is needed to fly the electric "Volocopter" helicopter?
The German transportation ministry has decided to create a new aircraft category for this machine.

From Aviation Week:


  Karlsruhe-based E-volo says the Ministry has commissioned a two- to three-year trial program to create a new category of ultralight aviation to cover the two-seat VC200 rotorcraft now in development. [...] Under the trial program, the German Ultralight Aircraft Association, Sport Aircraft Association and Federal Aviation Office will work with E-volo to create a manufacturing specification, legal regulations and training requirements for the new "Volocopter" ultralight rotorcraft category.


So according to this, the exact licence, and training requirements will be deteremined by the currently running trial program. It seems the manufacturer tries to position the craft as some sort of rotational-wing ultralight.