After making an impressive racecourse debut at Deauville at the end of July, Freddy Head's filly stepped up to Group Three level in the Prix du Calvados and ran out a comfortable winner.
The runner-up that day was the Karl Burke-trained Laurens, who claimed a last-gasp success in the May Hill Stakes on Town Moor.
"She is very well, but we are not going for the Cheveley Park," said Head.
"We have decided to keep her at home and the plan is to run in the Prix Marcel Boussac. I am pleased to see the form looks good. She is a very good filly, I think."
Polydream is a best priced 16-1 for the Qipco 1000 Guineas at Newmarket.