Treve, Leading Light and Meandre have all been supplemented at a cost of 100,000 euro for Sunday's Prix de l'Arc de Triomphe at Longchamp.
Criquette Head-Maarek's Treve is unbeaten, twice winning at Group One level, and will be reunited with Thierry Jarnet after Frankie Dettori fractured his ankle at Nottingham on Wednesday.
Aidan O'Brien's Leading Light claimed the Queen's Vase over two miles at Royal Ascot in June and dropped back in distance to win the Ladbrokes St Leger at Doncaster last month. He faces another two-furlong drop in trip this weekend.
Meandre, formerly trained by Andre Fabre and now with Arslangirej Savujev, was reinstated as the winner of the Preis von Europa on appeal this week after initially losing the race in the stewards' room.
The Fugue has been left in by John Gosden and not declared for the Prix de l'Opera.
O'Brien has taken out Camelot, leaving a field of 19 at the probable stage, with further withdrawals able to be made on Friday.