The Eels winger accepted an offer to play for Toulon over the 2017/18 European rugby season, with an option for a second year.
Radradra, 24, had a turbulent year in 2016, including injury, a Test debut for the Kangaroos and then domestic violence charges, which are due to be heard in court in February.
According to Parramatta chief executive Bernie Gurr, the Eels made a "very attractive" offer to Radradra to sign through the 2019 season, but Toulon's off was "substantially higher" than the NRL club's.
"We look forward to Semi being a most productive member of the 2017 Parramatta Eels playing squad and then we wish Semi well in his rugby union venture with Toulon," Gurr said.
The European rugby season runs from August to May, with Radradra able to join his new teammates in November.