Operator group Orange is reportedly being sued by a California-based startup regarding its PartyCall app for iOS and Android, which enables users to make voice calls via Facebook.

According to a Financial Times report, Telesocial claimed that the French company stole its intellectual property and used it to create PartyCall.

The complaint was filed with a court in California at the beginning of the week, and alleges that Orange “unlawfully obtained information to reverse engineer a knock-off product that Orange and Facebook would later go to claim they developed from scratch”.

The startup allowed Orange to have access to its own code during failed negotiations for a partnership in 2012. Stephane Richard, Orange CEO, subsequently unveiled PartyCall at a company conference in November 2012, together with Facebook COO, Sheryl Sandberg.

Telesocial is seeking damages from Orange, arguing that the unveiling of PartyCall by Orange should have been a “transformative moment that every start-up exists to chase, where valuations are catapulted overnight into the stratosphere”.

Orange stated that the legal action is based on similar arguments to those heard in courts in Paris over the past year when Telesocial had its claims rejected.

Telesocial was founded in 2008 and developed technology to enable calls to be made from social networks. Its discussions with Orange came about as it needed to partner with a mobile operator in order to drive uptake of the app, which was subsequently abandoned.