Complex sentence: The son returned to Europe to study at "l'Ecole des Ponts et Chaussées" (School of Bridges and Roads) in Paris, France, where he graduated in 1885 at the top of his class.
Split into simpler sentences: The son returned to Europe to study at "l'Ecole des Ponts et Chaussées" (the School of Bridges and Roads) in Paris, France. In 1885 he graduated from the School of Bridges and Roads at the top of his class.