The Prix du Lys is a Group 3 flat horse race in France open to three-year-old thoroughbred colts and geldings.
It is run at Longchamp over a distance of 2,400 metres (about 1½ miles), and it is scheduled to take place each year in May.
The event is named after Le Lys, a small forest close to Chantilly on the left bank of the Oise river.
It was established in 1922, and was originally open to colts and fillies, but not geldings.
The race's original distance was restored in 2001, and from this point it was staged at Longchamp.