Zarkava bids to defend her unbeaten record and add to her Classic haul with victory in Sunday's Prix de Diane at Chantilly.
The Alain de Royer-Dupre-trained filly won the Prix Marcel Boussac as a juvenile before notching an impressive victory in the French Guineas last month.
She is likely to be long odds-on to add the French Oaks to her CV but connections do have slight reservations as Zarkava attempts 10 furlongs for the first time.
"The form of her Guineas win is working out with (fourth-placed) Modern Look winning last weekend and the only question is going to be the distance," said Georges Rimaud, racing manager to owner the Aga Khan.
"She has never been over 10 furlongs before but we feel it should not be a big issue, although there are other good fillies in there.
"There is plenty of stamina on her dam's side so she should be OK, but you never know until you try for the first time.
"Without it being a worry, there is always a question mark until you know for sure.
"She's only had four starts but she has already won two Group Ones. She is a very good filly.
"I couldn't say if she is the best filly the Aga Khan has had but she is certainly one of a very special bunch.
"We have been lucky enough to have Darjina and Mandesha recently, some very good fillies, but this one is special.
"The trainer says this is one of his best and he should know because he has had plenty of good ones.
"Christophe (Soumillon, jockey) has always liked this filly and he always has confidence - we may have to temper that a bit though!
"There will be a bit of pressure on him, obviously, but he enjoys these big days and it is all in his hands.
"There are always options over a mile even if she stays 10 furlongs but I think we will be looking to stay at that trip, but there are no set objectives.
"Royal Ascot will probably come too soon but we will have to see how she does this weekend before we consider the Irish Oaks and see what the trainer and jockey think."
Zarkava faces 12 rivals in the 10-furlong event, headed by stablemates Belle Et Celebre, winner of the Prix Saint Alary, and the Frankie Dettori-ridden Leo's Starlet.
Goldikova, who finished second to Zarkava in the Guineas, reopposes while Andre Fabre's Proviso lines up alongside her stablemate Gagnoa, who will be ridden by Johnny Murtagh.
Aidan O'Brien runs Kitty Matcham while Jim Bolger sends Prima Luce to the race.