Trading Standards officers and police raided four homes in the Bishop Auckland, Crook and Peterlee areas.
More than 500 luxury items, claimed to be worth more than £10,000, were seized and five people arrested.
The items including branded clothing, trainers, perfumes and electrical hair styling products were being sold online, Durham County Council said.
The raids were carried out after officers monitored items being sold through websites.
The council said the items would have made the sellers more than £10,000, while genuine objects would have sold for £50,000.
Hundreds of suspected fake luxury goods have been seized in raids on houses in County Durham.