McAlister en route to Toulon
The 33-year-old former Blues outside half will join on a one-year deal from Toulouse with an option for a second season.
McAlister spent six seasons with Toulouse after spells at North Harbour, Auckland Blues and Sale Sharks.
He won the French title in his first season with Toulouse, scoring all their points in an 18-12 final victory over Toulon.
He has 30 New Zealand caps, scoring 153 points.
Incoming Toulon head coach Fabian Galthie had claimed in April that McAlister would join the club.