Complex sentence: The Prix Vermeille is a Group 1 flat horse race in France for three-year-old and above thoroughbred fillies and mares run over a distance of 2,400 metres (approximately 1 mile 4 furlongs) at Longchamp Racecourse in September.
Split into simpler sentences: The Prix Vermeille is a Group 1 flat horse race in France for three-year-old and above thoroughbred fillies and mares. It is run over a distance of 2,400 metres (approximately 1 mile 4 furlongs) at Longchamp Racecourse in September.