Her brother, Alexis III Loir (1712–1785), was a renowned sculptor.
She studied under Jean François de Troy (1679–1752), director of the French Academy in Rome, where Marianne stayed between 1738 and 1746.
She became a member of the Académie des Beaux-Arts in Marseille in 1762, and seems to have stayed at Pau for a time in the 1720s and Toulouse.
In 1763 she was in Paris, where she completed a portrait of the young Antoine Duplas on 1 September.
She died in Paris, 11 May 1783[2] Works include: Drawings, watercolors Paintings Citations Sources