Henin, who is competing for the first time in the 2007 season, beat France's Tatiana Golovin, 6-2, 3-6, 6-3. Mauresmo, who like Golovin, is playing in front of a home crowd, downed Russia's Anna Chakvetadze, the eighth seed, 7-6 (7-5), 7-5.
Also winning were No. 4 Nadia Petrova, who beat seventh-seeded Dinara Safina of Russia, 6-3, 6-2; and the Czech Republic's Lucie Safarova, who knocked off No. 3 Svetlana Kuznetsova of Russia, 6-3, 6-4.
In Saturday's semis, Henin plays Safarova, and Mauresmo faces the challenge of Petrova.
The survivors will play Sunday for a winner's check of $88,265.