Facebook has filed an intellectual property lawsuit against a German company that it says is running a "knock-off" version of the social networking site.

Facebook has accused "StudiVZ", that boasts 10 million users in Germany, Austria and Switzerland, of "copying the look, feel, features and services" of the Facebook site in a complaint filed in California.

Facebook says StudiVZ has copied entire portions of Facebook, including features such as the Wall, stating that differences between the two sites were "nominal" with StudiVZ just "replacing Facebook’s blue colour scheme with a red one".

Facebook, that's recently launched a German-language version of its site, says it is "seeking to end StudiVZ’s illegal activity to ensure that users are not confused and that Facebook’s reputation remains unharmed".