The 26-year-old, who joined Lyon in July 2008 from French rivals Stade Rennes, has won almost 60 caps for Ghana.
Sunderland have the option to buy Mensah at the end of the loan spell, the club said on their website.
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The 26-year-old, who joined Lyon in July 2008 from French rivals Stade Rennes, has won almost 60 caps for Ghana.
Sunderland have the option to buy Mensah at the end of the loan spell, the club said on their website.
