Armitage's contract was due to end at the end of this season.
Toulon also said on their website (www.rctoulon.com) that Top 14 rivals Montpellier's flanker Mamuka Gorgodze of Georgia would join next season on a three-year deal.
Armitage had hinted last month he could quit Toulon amid speculation that Wales open side flanker Sam Warburton could join the Top 14 club
Armitage has not played for England since 2010 and coach Stuart Lancaster does not consider players who are with foreign clubs.
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