Polański appeared in court on Tuesday in Kraków, southern Poland, in the latest hearing in the proceedings, which began in February.
“It was very important for me to be here,” the director said.
“I wanted to know which documents were presented and considered by the court,” he added.
Documents sent from the US and Switzerland were among those examined.
Polański seemed in relatively upbeat spirits, judging by his interactions with his lawyers, Jerzy Stachowicz and Jan Olszewski.
At one point the director plucked his smartphone from his pocket, and apparently began filming the judge and journalists gathered in the courtroom.
Polański fled the US in February 1978, shortly before being sentenced for unlawful sex with a 13-year-old girl. He settled in Paris, where he has been chiefly based ever since.
In 2009, while entering Switzerland to receive a prize at the Zurich Film Festival, he was arrested, as a US request for his extradition had been freshly submitted. However, Swiss authorities ultimately backed down after keeping him under house arrest for several months.
The director returned to France, but he occasionally visited Poland, where he had grown up.
US authorities became aware that Polański was in Poland again last autumn after he attended the opening of a museum in Warsaw. The director hopes to make his next film in Poland.
An extradition request was submitted by the US to Poland, and the first hearing was held in February.
Although the last court session is scheduled for 30 October, Poland's minister of justice has the right to overturn the verdict.
However, a general election is due to held on 25 October, and its outcome may delay the process. (nh/rk)