Paul Guigou is best known for his Provençal landscapes of the Durance Valley. The region, later made famous by Cézanne and Van Gogh, inspired the artist with its brilliant light and rich color. A self-taught artist, Guigou painted en plein air in a manner that presaged the work of the Impressionists. His paintings attracted the attention of Emile Loubon, the director of the Ecole des Beaux-Arts in Marseille, who introduced him to another Provenal painter of renown, Alphonse Monticelli, with whom Guigou exhibited at the Société Artistiques des Bouches-du-Rhone. During trips to Paris in 1855 and 1859 Guigou made the acquaintance of Dr. Paul-Ferdinand Gachet, Van Gogh's patron, who later bought thirty paintings from his estate sale.
Guigou's portrayal of the unique landscape of the region can be understood not only as a visual recreation of the topography but also as a celebration of its uniqueness. The rapid social changes of the 1850s and 1860s called for an abandonment of the local language and customs in favor of French nationalism and angered Provenal leaders. At the same time, the region saw an influx of population from other parts of the country that threatened its individuality. The Marseilles that Guigou had depicted in his earliest works rapidly changed into a major international port with the opening of the Suez Canal in 1867. In response to this political climate native Provenal artists such as Guigou and the poet Frederic Mistral sought to celebrate their region through their art. Reflecting on Guigou's contribution to the Provenal renewal, Mistral said, 'I consider Paul Guigou the greatest painter of Provence. No one could paint better than him the luminosity of our beautiful land, the rugged poetry of its rocky and powdery soil. With great sincerity of vision, he made a truthful and faithful portrait of this little nation. He does not yet have the place in the world of art which he deserves, but that will come' (quoted in A. Sheon, Paul Guigou, exh. cat., 1987, op. cit.).
Une matinée d'automne à Cernay was painted in 1866 when Guigou was at his prime as an artist. The previous year, Guigou had won a medal at the Salon for Vue de l'Ile Saint-Honorat et les Bords de la Creuse and he chose to submit Une matinée d'automne à Cernay as a follow up to that success. Working on a large scale, Guigou deftly captures the transitory effects of the light against the landscape. The intense colors of the riverbank are portrayed with sharp focus as if magnified by the clear autumn air. 'It is a seasonal light, varying from the heated skies that Vincent van Gogh painted in Arles and Saint-Remy, to the thin, cold light that accompanies the strong wind called Le mistral, which blows down the Rhone Valley to the sea in the late fall and winter' (ibid., op. pl. 12). Une matinée d'automne à Cernany depicts a pictueresque view along the banks of a river. The presence of the small, isolated figures underscores man's solitude within this expansive landscape, which was a recurrent motif in Guigou's paintings. An article written in 1870 by the art critic Duret described Guigou's mature style in the following terms, '..he has now succeeded in painting landscapes in which the sincerity of tones and the accenting of colors has now been blended into a harmonious effect...Guigou excels at extending a perspective, and at arranging the middle grounds against a well composed distant background...his manner of using direct accents to render the coloring of the water, rocks, mountains and by the bright, lively light that he projects onto the countryside...Guigou paints space and distance' (quoted in 'Un grand peintre de la Provence, Paul Guigou', L'Art et les Artistes, vol. XV, April-September 1912, pp. 97-99).