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In the 2018 biographical drama film "Colette," Fiona Shaw portrays Mathilde de Morny, the Marquise de Belbeuf, a wealthy Parisian socialite and friend of the eponymous protagonist, played by Keira Knightley. Shaw's character provides both moral and financial support to Colette as she navigates her rise to fame as a writer and the complexities of her personal life amidst societal constraints.