Sistercharlie was second, with Terrakova third.
Frankie Dettori managed to navigate Shutter Speed into a good position but she could not reply as Senga found top gear in the home straight.
Senga is trained by Pascal Bary and was ridden by 39-year-old Frenchman Stephane Pasquier.
Dettori, 46, was competing for the first time since he was thrown from his mount before racing at Great Yarmouth on Tuesday.
The Italian, who has ridden 56 winners at Royal Ascot, fell after Tivoli seemed to be startled.
This year's Royal Ascot meeting starts on Tuesday.
Shutter Speed finished fourth and Rhododendron was pulled up by jockey Ryan Moore as Senga claimed victory at the Prix de Diane in Chantilly.