Complex sentence: French Prime Minister Paul Reynaud dismissed his supreme military commander, Maurice Gamelin, and replaced him with the 73-year old Maxime Weygand, and named the 84-year-old Philippe Petain, a hero of the First World War, as deputy prime minister.
Split into simpler sentences: French Prime Minister Paul Reynaud dismissed his supreme military commander, Maurice Gamelin, and replaced him with the 73-year old Maxime Weygand. He also named the 84-year-old Philippe Pétain, a hero of the First World War, as deputy prime minister.