Edouard Mendy has agreed terms with Chelsea and put pen to paper on a five-year deal, however, Rennes are looking to land one of Chelsea's first-team squad as part of the transfer deal.
According to Telefoot, the Ligue 1 side want Fikayo Tomori as a makeweight as part of Mendy's imminent exit.
However, it is unclear if the French outfit want Tomori on a permanent deal or just on a season-long loan.
French outlet L'Equipe claim Rennes had also demanded a €40m (£37m) fee for Mendy along with the option of signing Olivier Giroud.
Giroud is facing an uncertain future at the club due to the arrival of Timo Werner.
Pressed on a deal for Mendy this week, Lampard was unwilling to comment on any transfer information.
“Not at the moment, not at the moment, no,” Lampard told Sky Sports on Monday when asked about any new arrivals.
This article was most recently revised and updated 2 years ago