Her headwear forms part of the traditional habit worn by nuns, but was deemed an "ostentatious religious symbol" by social workers who said it breached France's secular values.
Social workers in eastern France wrote to the nun, who is in her 70s, when she applied for a room in the Résidences Autonomuie, a local care home in Vesoul.
In the letter, they told the nun, that she would be eligible for a spot in the care home if she removed her veil.
The letter said: "In order to respect signs of secularism, any ostentatious signs of belonging to a religious community cannot be accepted."
The mayor of Vasoul has pledged to overturn the decision, and said the social workers had made an "error in interpretation" of secular values. Mayor Alain Chrétien said the ban on religious symbols applied to government employees, including care home workers, but not to residents.
In recent years, officials have used a century old law that separates the church and the state to ban Muslims employed by government bodies from wearing headscarves on the grounds that the garment would reintroduce religion into French public life.
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