Lassay-les-Châteaux is a commune in the Mayenne department in north-western France. It was created in 1973 by the merger of three forme…Lassay-les-Châteaux is a commune in the Mayenne department in north-western France. It was created in 1973 by the merger of three former communes: Lassay, La Baroche-Gondouin and Melleray-la-Vallée. Lassay-les-Châteaux is classified as a Petites Cités de Caractère, or Small City of Character. The small town of character label is awarded to small municipalities boasting a high-quality, coherent architectural heritage, and undertake to preserve their heritage and promote it to inhabitants and visitors.