The fourth-seeded Parmentier upset top-seeded Agnes Szavay 6-4, 6-2 in Saturday's semifinal, while 237th-ranked Hradecka defeated Mariya Koryttseva of Ukraine 6-3, 6-2.
It will be Parmentier's second career final after winning in Tashkent, Uzbekistan, last year, and the first final for the 23-year-old Hradecka. The Czech won 11 titles on the ITF women's circuit but had previously never passed the second round of a WTA Tour event.
Hradecka won three qualifying matches to enter the main draw, where she conceded just 17 games in four straight-set victories.
The 53rd-ranked Parmentier saved seven break points against Szavay to hold serve throughout. She broke the 14th-ranked Hungarian once in the opening set and twice in the second.
In the quarterfinals earlier Saturday, Parmentier beat last year's finalist Yvonne Meusburger of Austria 7-6 (3), 6-3 after rallying from an early break in the first set and holding off four break points in the opening game of the second.
Szavay reached the semifinals by defeating seventh-seeded Iveta Benesova 6-2, 6-2, despite struggling with her serve and double-faulting eight times.
Koryttseva eased past 260th-ranked Tereza Hladikova of Czech Republic 6-3, 6-1 to set up the semifinal meeting with Hradecka, who beat Patricia Mayr of Austria 6-3, 6-1. Koryttseva fell behind 3-1 in the opening set before winning 11 of the next 12 games.
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