Born in Le Puy- en-Velay, a small town in Auvergne. Cottet moved to Paris in 1882 and studied under Puvis de Chavannes and Alfred Roll. He debuted at the Salon in 1889. In 1890, he took part in the establishment of the Société Nationale des Beaux Arts. He traveled to Algeria and Egypt twice from 1892. He also visited Brittany for the first time that year. This trip had a decisive influence on his artistic style. From then on, he did landscapes and views of the life in Brittany characterized sorrowful religious feelings in dark color tones. He won a gold prize at the Expoisition Universelle held in Paris in 1900.
（source：Masterpieces of the National Museum of Western Art, Tokyo, 2009, p.162)