Diarra, the Olympique de Marseille midfielder, took to social media on Saturday to confirm that Asta Diakite, a cousin he described as being like a "big sister" to him, had died in Friday's atrocities.
Diarra had been playing in the France-Germany international at France's national stadium when explosions could be heard outside.
"It is with a heavy heart that I speak today," Diarra, the former Real Madrid, Arsenal and Chelsea defensive midfielder, said on his official Twitter account.
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"I was personally touched by these attacks. My cousin, Asta Diakite, was among the victims of one of the shootings which took place yesterday, as many other hundreds of innocent French people. She was for me a point of reference, a support, a big sister.
"In this climate of terror, it is important for all of us, who are representatives of our country and of diversity, to speak up and to remain unified in the face of a horror which has no colour, nor religion.
"Together, we must defend love, respect and peace. Thank you to all of you for your testimonies and your messages, take care of yourself and your loved ones, and (I hope) that our victims rest in peace."
As well as the 129 known to have died, 352 people were also wounded in the attacks on Friday in Paris. It was later confirmed there were two suicide attacks and one bombing near the Stade de France, killing three people.
(Reporting by Julien Pretot and Ian Chadband, Editing by Pritha Sarkar)
