The 29-year-old asked leave the Aviva Premiership club, where he only made for appearances since making his debut against Wasps at Wembley on Boxing day, paving the way for him to join Jonny Wilkinson at Toulon.
“We wish Gavin all the best for the future as he continues his return to the highest level of the game,” said Sarries chief Nigel Wray.
Henson returned to the sport just six weeks ago after a 21-month absence but recent speculation has linked the Strictly Come Dancing star with a move to the French Top 14 side on a short-term deal until the end of the season.
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BIOGRAPHY: Marcus Rashford