The club announced the news on their official Twitter page on Friday, with Cissokho securing a return to the Premier League after spending last season on loan at Liverpool.
Cissokho made 19 appearances in all competitions at Anfield, including 12 league starts as Brendan Rodgers' men finished second.
That temporary deal came after one season at Valencia, where he made 25 La Liga appearances during 2012-13.
The former Porto and Lyon man has one France cap to his name, earned in a friendly against Norway in 2010, and arrives at Villa Park to help shore up a defence that shipped 61 league goals last season.
Villa also announced on that 21-year-old midfielder Daniel Johnson has signed for League One newcomers Chesterfield on a three-month loan deal.
