The closure of the plant on the border with Germany is part of a policy change aimed at reducing France’s dependence on nuclear power.
Germany has long asked for the plant to be closed.
Workers at electricity giant EDF, which operates Fessenheim and 18 other nuclear power plants in France, described the shutdown as a blow.
However, it was celebrated as a victory for anti-nuclear activists.
Andre Hatz, president of the Stop Fessenheim association, said he was pleased that the 50-year battle to close the factory had ended, but was concerned about what remained.
He said: “(I am) happy because of the definitive shutdown of the nuclear power plant, worried about the fuels that will always be there for three years, in pools that are not supported without a security system in place, and that being really necessary. ”
The closure of Fessenheim still leaves France with 56 pressurized water reactors in 18 factories. Nuclear power supplies France with almost three quarters of its electricity, more than any other country.
As part of an energy strategy defined in 2018 by President Emmanuel Macron, this balance is now changing, with greater importance given to renewable energies.
The government has outlined plans for 12 additional reactor shutdowns and that only half of French electricity will still come from nuclear power by 2035.