Ziani won the French Cup with Sochaux last season
Algeria midfielder Karim Ziani has joined French side Olympique Marseille from Ligue 1 rivals Sochaux.
The 24-year-old signed a four-year deal after the Champions League contenders parted with US$11m.
Ziani joined Sochaux a year ago after being voted Ligue 2 Players' Player of the Year for his contribution to Lorient's promotion to the top flight.
He made 36 league appearances last season and scored eight goals.
The Algerian was a member of the Sochaux side that defeated Marseille in the French Cup final to earn a place in the Uefa Cup.
Ziani is expected to be a key player for Marseille, who qualified for the group stage of the Champions League following a four-year absence.