"Downton Abbey" star Nathalie Baye reportedly died Friday. She died in the evening at her home in Paris following a Lewy body dementia diagnosis, her family told French press agency, AFP . Lewy body dementia is one of the most common forms of dementia, and symptoms include visual hallucinations, according to Alzheimers.gov . It leads to problems with thinking, movement, behavior, and mood. Nathalie played Madame de Montmirail in the 2022 film, "Downton Abbey: A New Era." Her character is a