Complex sentence: The Prix La Rochette is a Group 3 flat horse race in France for two-year-old thoroughbreds run over a distance of 1,400 metres (approximately 7 furlongs) at Longchamp Racecourse in September.
Split into simpler sentences: The Prix La Rochette is a Group 3 flat horse race in France for two-year-old thoroughbreds. It is run over a distance of 1,400 metres (approximately 7 furlongs) at Longchamp Racecourse in September.