sentence1: The north tower, the Tour Saint-Romain, has the sober simplicity of the cathedral's early Gothic beginnings in the 12th century, while the taller, more elaborate south tower, the Tour de Beurre, is Flamboyant Gothic of the 15th century.
sentence2: Unlike the Tour Saint-Romain, the Tour de Beurre represents Flamboyant Gothic design from the 15th century.