Facebook yesterday filed an intellectual property lawsuit against a German company that it has accused of running a "knock-off" of the social networking website.

In a complaint filed in a California court, Facebook accused StudiVZ, a German company that claims to be "the most successful social network in Germany, Austria and Switzerland", of "copying the look, feel, features and services" of the Facebook site.

The lawsuit comes several months after Facebook, which claims more than 80m active users, launched a German language version of its own website. That site has since struggled to gain traction among German users, according to one person close to the company.

In its complaint, Facebook accused StudiVZ of copying entire portions of the site's design, including features such as Facebook's distinctive "wall", which allows users to leave messages on each other's profile pages.

It claimed that any differences between the two sites were "nominal" and accused StudiVZ of merely "replacing Facebook's blue colour scheme with a red one".

Facebook said it was "seeking to end StudiVZ's illegal activity to ensure that users are not confused and that Facebook's reputation remains unharmed".

StudiVZ could not be reached for comment. The site, which is based in Berlin, was bought last year by Verlagsgruppe Georg von Holtzbrinck, a German publishing company, which also could not be reached.

Facebook, which was founded in 2004 by Harvard student Mark Zuckerberg, recently settled its own intellectual property dispute. It resolved a legal battle with ConnectU, a rival website launched at Harvard around the same time, whose owners claimed Mr Zuckerberg stole its idea for a site that allowed Harvard students to connect to each other online.