More than 500 copied DVDs and CDs with an estimated value of £7,500 were seized following a raid at a car boot sale.
Officers from Stockton Borough Council's trading standards, backed by Cleveland Police, carried out a series of raids at Blakeston car boot sale, Norton, on Sunday.
The raids were in direct response to complaints received from members of the public that copied DVDs and CDs were openly on sale at the site.
Trading standards officers had previously gathered intelligence and made test purchases, which culminated in the raid and the merchandise being seized from three stalls.
David Kitching, the council's trading standards manager, said: "Officers will continue to visit car boot sales and fairs in the Stockton area and anyone discovered selling counterfeit goods may face prosecution."
Councillor Martyn Ingram, the council's cabinet member for housing and community safety said: "The selling of copied discs will not be tolerated.
"The damage to local and national economy is enormous and it is essential to protect reputable traders in the area."
Two men from Stockton and a woman from Peterlee will face questioning at a later date.
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