The 27-year-old arrives from Atlético Madrid where she played four seasons.
She played the Euro this summer in England with the France team, with a surprise start in the first match against Italy (5-1), and another against Iceland (1-1), still in group stage.
"She will provide vital experience in the Champions League and European competition for our young players, and real maturity to our defensive game," coach Marc Skinner said in a statement.
Appreciated by the coach of the Blue Corinne Deacon who has sometimes given him the captain's armband in recent seasons, Tounkara has 35 selections.
At Les Bleues in central defense, it is nevertheless regularly barred by the duo Wendie Renard - Griedge Mbock, who plays in Lyon.
© 2022 AFP