Eighth-seeded Kirsten Flipkens of Belgium beat Yvonne Meusburger of Austria 6-1 6-3 at the Open GDF Suez on Thursday to set up a quarter-final against top-seeded Maria Sharapova.
Last year's runner-up, Sara Errani, also reached the last eight in straight sets.
Flipkens converted all four of her break points against Meusburger, and the third-seeded Errani broke Karin Knapp's serve five times to win their all-Italian match 6-4 6-3.
Elina Svitolina of Ukraine and Andrea Petkovic of Germany also advanced with ease.
Svitolina beat Galina Voskoboeva of Kazakhstan 6-1 6-2 and next plays Errani, while Petkovic downed recently-crowned Australian Open mixed doubles champion Kristina Mladenovic from France 6-4 6-2.
Petkovic next faces Frenchwoman Alize Cornet, who needed three hours to beat Czech lucky loser Barbora Zahlavova Strycova 6-3 6-7 (2-7) 6-3 in a match featuring 10 breaks of serve.
Zahlavova Strycova replaced second-seeded Petra Kvitova of the Czech Republic after she pulled out because of a sore throat.