Ferrer showed his class with a convincing 6-2 7-5 win over the 2008 champion. The world number four was always a step ahead of Tsonga, who huffed and puffed but failed to earn one break point never mind a break of serve in the match.
The Spaniard will face French qualifier Michael Llodra, a figure posted at 121 in the world, in the semis after his serve and volley brilliance saw him complete a 7-6 (7-4) 6-3 win over American Sam Querrey in Friday's final last-eight match-up.
French hope Gilles Simon also reached the last four of the event - for the first time - with a convincing 6-4 6-4 win over a misfiring Tomas Berdych.
Polish qualifier Janowicz, 21, lies in wait for Simon in the semi-finals after he produced another breathtaking performance in recovering to complete a 3-6 6-1 4-1 win over world number nine Janko Tipsarevic, who retired apparently feeling groggy with his opponent on the cusp of victory.
Tsonga, who also secured a berth in the World Tour Finals on Thursday, was never in the hunt against a focused Ferrer, the highest-ranked player left in the draw after Andy Murray and world number two Novak Djokovic had been dumped out.
Ferrer, who did not face a single break point, raced through the first set and although the sixth-seeded Frenchman increased the pressure in the second, Tsonga was too sloppy to seriously trouble his opponent.
Tsonga was 0-40 down in the 12th game. He saved two match points with decent first serves but then sent a routine forehand wide on the third.
"It's complicated to play at Bercy just before the Tour Finals but I wanted to win the tournament once more," he said. "As soon as tomorrow I'll be on court in London to practice."
Janowicz, the world number 69, proved his win over US Open champion Murray on Thursday was no fluke as he almost battered Tipsarevic into submission hitting 33 winners to only 11 from his Serbian opponent.
"This is something magical for me. I don't know what is going on in my heart right now," said Janowicz. "I feel like I am going to wake up and everything has gone. It is going to take some time to understand what is going on, but I have to focus on my next match.
"In the second and third sets, I played unbelievable tennis. I couldn't play better than that. I don't how I will win my next match. I need a few hours rest."
In the opening quarter-final of the day, Berdych was penalised for throwing in a series of misplaced shots against home favourite Simon, making 43 unforced errors compared to only 21 by the crafty Frenchman, who utilised the angles of the court to trouble the more powerful Berdych, whose lack of consistency on the forehand side proved to be his downfall.
The unseeded Simon, who reached the quarter-finals after Japanese Kei Nishikori withdrew with an ankle injury, had too much pace for Berdych in front of his home crowd.
World number six Berdych is already assured of a place in next week's ATP World Tour finals in London, but will surely have to recover his gait to trouble the leading names in the game when he gets there.
In particular, Berdych will wonder what went wrong in the second set having led 3-0 and 4-1 only to see Simon recover to win the last five games of the match to progress to a meeting with Janowicz that should be unpredictable at the very least.
Michael Llodra (France) beat Sam Querrey (U.S.) 7-6(4) 6-3 4-6
4-David Ferrer (Spain) beat 6-Jo-Wilfried Tsonga (France) 6-2 7-5
Jerzy Janowicz (Poland) beat 8-Janko Tipsarevic (Serbia) 3-6 6-1 4-1 (Tipsarevic retired)
Gilles Simon (France) beat 5-Tomas Berdych (Czech Republic) 6-4 6-4