From the German Patent and Trademark Office...

Opposition

"Anybody can oppose the grant of a patent within three months from the publication of the patent specification. If no opposition is filed, the patent becomes legally valid upon expiry of the opposition period. The patent will then become valid retroactively from the date of filing for a period of up to 20 years.

The notice of opposition allows the opponent to state the reasons why he considers the patent to be unlawful. Within the scope of the fee-based opposition procedure, a panel of members of a patent division of the DPMA re-examines whether the patent meets requirements for grant or maintenance. The patent will be either revoked or maintained as granted or in an amended form of more limited scope.

Appeals against decisions in opposition procedures can be lodged at the Federal Patent Court (Bundespatentgericht).

Even after expiry of the opposition period, a patent in force can be challenged by an action for the declaration of nullity brought before the Federal Patent Court."

What we just went though In Germany is the action brought to the Federal Patent Court...which looks like the end of the process...IMO