The 41 objects, which include coins and decorated cups and bowls from the 13th and 14th centuries, were among 309 items seized at the market in May 2005.
"The goods was described as 'ethnic goods' coming from Thailand," said Gen. Giovanni Nistri, who heads the art squad of the Carabinieri paramilitary police. Already, several pieces from the stash have been returned to Pakistan, he said.
Two people - a Pakistani and an Italian - have been charged with dealing in illegal artifacts in connection with the seizure, Nistri said.
Nistri said art squad police routinely check antiquities markets, since it was "the most dangerous channel" for illegal antiquities to enter the art market.
Italian Culture Minister Francesco Rutelli and Iran's ambassador to Italy, Abolfazl Zohrevand, signed documents at a press conference at the Culture Ministry officially returning the items to Tehran.