Goals early in each half from David Luiz and Edinson Cavani secured passage into the last four for Laurent Blanc's side – a stage they last reached in 2011 – as well as their first victory over Monaco since the Coupe de France final in 2010.
Monaco prevented PSG from going top of Ligue 1 when the sides met at the weekend, with Leonardo Jardim's side holding the champions to a goalless draw, but they were behind after only three minutes when Luiz grabbed his third goal of the campaign.
The visitors went close to equalising before the break through Alain Traore's ambitious effort that rattled the post, though Cavani's 52nd-minute strike made it comfortable for PSG.
Blanc's men continued to press for a third, with Cavani and Javier Pastore both striking the woodwork, but Monaco failed to make PSG pay for their below-par finishing as the hosts joined Saint-Etienne in the penultimate round.
PSG, without star player Zlatan Ibrahimovic for the second consecutive match due to suspension, made just three changes to the line-up that started at the Stade Louis II on Sunday, while only four of Monaco's starting XI were retained by Jardim.
And Blanc's decision paid dividends as PSG made a storming start – though shoddy defending from the visitors played a large part in their early goal.
After originally heading into the ground after connecting with a corner from the right, Luiz reacted quickest to nod home past Maarten Stekelenburg.
PSG went close to doubling their advantage soon after as Cavani carved open the Monaco defence with ease, but the forward's effort trickled harmlessly into the arms of Stekelenburg.
Despite PSG's dominance, parity was almost restored when Traore clipped the upright with a blistering long-range free-kick.
That chance seemed to act as a wake-up call for the hosts as they moved forward once again, and Pastore should have done better after latching onto Ezequiel Lavezzi's free-kick, but the Argentine's header looped over the crossbar.
However, PSG did not have to wait long after the interval to extend their lead – Marco Verratti playing in Cavani, who took it coolly round Stekelenburg before guiding it in off the left-hand post.
PSG then squandered several opportunities to put the result beyond all doubt as the hour-mark approached, Pastore and Cavani both striking the post in the space of a minute before the former ballooned a shot high over the bar from the edge of the six-yard box.
Monaco did manage to steady the ship somewhat, with Joao Moutinho coming on to solidify the midfield, but PSG remained untroubled and eased comfortably into the final four.
