Frankfurter Verlagsgruppe, a German publishing company, sued Wikimedia Deutschland over the article about itself in the German Wikipedia. Last week, the Cologne Landgericht (regional court) ruled that the critical remarks in the article (which were citing a report from a consumer magazine of German TV station ZDF and other sources) were legal. More generally, it rejected the plaintiff's arguments that Wikimedia Deutschland could be held accountable for content in the German Wikipedia because of its relationship with the Wikimedia Foundation, because of its ownership of wikipedia.de (which until last summer had been a domain redirect to de.wikipedia.org), or because it was supposedly "hiring admins" to oversee content.
Frankfurter Verlagsgruppe has also announced its intent to appeal the decision. 
Relevant links regarding this matter (all in German) include:
Previous court cases where plaintiffs tried unsuccessfully to hold Wikimedia Deutschland accountable for content of the German Wikipedia included a 2006 case involving Tron (hacker) (see archived story) and a 2007 complaint by advocacy group INSM because of an anonymous remark on an article talk page.