PARIS — The City of Light is about to get dimmer.

As of July, all shops and offices in France will have to shut off their lights at night, under a government decree issued on Wednesday.

The decree, from the Environment Ministry, is intended to save energy and “reduce the print of artificial lighting on the nocturnal environment.”

France is proud of its lights. Tourists cherish the Christmas illuminations on the Champs-Élysées, the 20,000 flashing bulbs on the Eiffel Tower and the bright, imaginative shop windows of large department stores like Printemps and Galeries Lafayette.

Major attractions like the Eiffel Tower will remain lighted, and local authorities can make exceptions for Christmas lighting and other celebrations. But France has decided to be “a pioneer” in preventing light pollution, said Delphine Batho, the environment minister.