Tsonga was down an early break but broke back to get to 4-4 and never looked back in a 7-5, 6-3, 6-3 win that gave him his fourth Grand Slam semifinal berth but first in the French Open. He is seeking to become the first French player since Yannick Noah in 1983 to win the event in Paris.
Tsonga, the No. 6 seed, only faced three break points on the day. Federer converted one in the fifth game of the match but didn't get another until he answered a Tsonga break that opened the third set. Tsonga went up 4-3 with his fifth break and finished the match with yet another in beating Federer for just the fourth time in 13 meetings.
Ferrer raced past 32nd-seeded Tommy Robredo 6-2, 6-1, 6-1 in 85 minutes. He had a pair of first-set breaks, closing with a break at love. He allowed Robredo just 17 points in the second set and 10 in the third in winning his fifth consecutive match in the tournament in straight sets.
Ferrer took nearly two-thirds of the points against Robredo, including 76 percent on serve and 54 percent when receiving.
This marks the second consecutive year for Ferrer to reach the French Open semifinals and sixth time overall, including four of the last five, he's made a major tournament semifinals. However, Ferrer is yet to play in a Grand Slam final.
Ferrer is 2-1 in his career versus Tsonga, whose sole trip to a major tournament final came in the 2008 Australian Open.
World No. 1 Novak Djokovic is to play 12th-seeded Tommy Haas and third-seeded and two-time defending champion Rafael Nadal goes against No. 9-seeded Stanislas Wawrinka in matches Wednesday to decide the other semifinalists.