Djokovic overcame his recent struggles with an easy 6-3, 6-3 win over unseeded German Mischa Zverev.
The Serbian made 73 percent of his first serves and did not face a break point the entire match.
"I was playing all the right shots at the right time, being very consistent from all sides, especially on the return," Djokovic said 24 hours after he struggled in his 7-5, 6-4 victory against unseeded Jan Hernych of the Czech Republic.
Simon, the second seed, beat fellow Frenchman Julien Benneteau, 6-2, 6-4.
Tsonga, the fourth seed, rallied to down No. 8 Feliciano Lopez of Spain, 6-2, 6-7 (1-7), 6-4; while Frenchman Michael Llodra outlasted Russia's Mikhail Youzhny, 7-6 (7-4), 7-6 (7-3).
In Saturday's semis, Djokovic faces Tsonga, and Simon plays Llodra.
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