Complex sentence: When the news reached Paris on 3 September, shocked and angry crowds came out into the streets, the Empress Eugenie, the regent of the Emperor, fled the city, and the Government of the Second Empire swiftly collapsed.
Split into simpler sentences: When the news reached Paris on 3 September, shocked and angry crowds came out into the streets. The Empress Eugenie, the regent of the Emperor, fled the city, and the Government of the Second Empire swiftly collapsed.