"A patent granted by the EPO does not lead to a single European Union-wide patent enforceable before one single court, but rather to independent national patents enforceable by national courts according to different national legislations and procedures."
"A European patent is also non-unitary in that it may be revoked in one Contracting State while maintained in another. However, a national court in one Contracting State may not revoke a European patent in another Contracting State."
This is a bit surprising. At the beginning of the Samsung vs Apple trials, also in Germany, it was widely reported that the german ruling would have EU-wide effects. Those were patent cases as well...
Maybe the difference is between invalidating patents and deciding whether a patent is infringed by another party.
http://en.wikipedia.org/wiki/European_patent_law