The meeting, at the UN General Assembly in New York on Tuesday night, was the first time Jens Stoltenberg had managed to to meet Joseph Kabila to argue Norway's case.
"They were positive talks," Stoltenberg told NTB. "President Kabila said that this was a difficult issue for them, but I feel that he listened. When and if we get a solution to this, it's too early to tell."
Efforts to bring Joshua French back home have intensified since his Norwegian colleague Tjostolv Moland was found dead in the cell they shared in prison in Kabila.
French has served four years in prison after the two were convicted of murdering their driver in 2009.
"We believe that the French should not continue his sentence in the Congo," the Prime Minister said.