There may be fresh competition for the Frenchman, but Chelsea are said to be in pole position - even if they are up to €10m short at present.
Koulibaly has signed, though the collapse of a second deal has upped the stakes for a Kimpembe move.
Chelsea could follow up on the Koulibaly and Ake deals by signing Presnel Kimpembe from PSG, with talks now underway.
Thomas Tuchel wanted a rebuild of his Chelsea defence and that is firmly underway at Stamford Bridge.
The PSG defender is one of a number of players in his position Chelsea are keeping tabs on - but could break a particular Blues transfer record.
Chelsea have fresh rivals for Presnel Kimpembe, with Real Madrid now monitoring the PSG defender according to a report
The PSG defender could effectively replace Andreas Christensen, whose departure as a free agent has formally been confirmed.
Rudiger's exit had been on the cards for months and has now been officially confirmed by both clubs.
A verbal agreement is in place on one deal, while Tuchel has a particular preference over the second.
The Blues remain interested in a defender their coach has an existing relationship with, but two Premier League rivals are also now keen
The Blues plan to spend big money on their next transfer arrivals - with three names who play for France very much on Tuchel's wishlist
Chelsea boss Thomas Tuchel is aiming to replace Antonio Rudiger with one of his former stars at Paris Saint-Germain, according to reports
Chelsea are eyeing an audacious PSG raid after a recent development left the player in question fearing what the future holds.
Arsenal manager Unai Emery reportedly wants to sign a £35m-rated Paris Saint-Germain defender this summer.
Bayern Munich winger Kingsley Coman has told a reported Liverpool target he would be better staying at PSG than moving to Anfield.
Liverpool and Inter Milan both look set for disappointment in their attempts to sign a talented PSG defender.