Born in Lannoy, Norway in the middle of the nineteenth century, Rossert’s exact dates are unknown. He was a versatile painter having been a pupil of three very prominent Parisian artists of the day, Alexis Nicolas Noel (1792-1871), Karl Ernest R. H. S. Lehmann (1814-1882) himself a pupil of Jean-Auguste-Dominique Ingres (1780-1867) and Charles E. A. C. Durand (1883-1917) an extremely well travelled and accomplished artist who's influence cast a shadow in artistic circles right across Europe especially in Spain and Rome and in Paris.
Rossert’s debut in the Paris Salon was in 1875, and he was to exhibit regularly there from that date, showing work in both oils and watercolour. His style was quite impressionistic and he enjoyed painting ‘La Belle Epoque’ with beautiful ladies promenading along the banks of the Seine, or at a flower market similarly to Luigi Loir (1845-1916), Jean Beraud (1849-1936) and Louis Marie de Schryver (1862-1942), but he also painted marine subjects that can be likened to the work of Dutchman Johan Jongkind (1819-1891).
The museum of Saint Brieue has a watercolour example of his work, which is a marine scene, and the museum of Rochelle has various examples.