France to have lights turned off From July 1, all non-residential buildings will have to switch off interior lights one hour after the last worker leaves the premises. All exterior and shop window lighting will have to be turned off by 1am. Local authorities will be able to allow exceptions for Christmas lighting and other local events. The new law will save about two terawatt/hours of electricity a year - the equivalent of the annual consumption of 750,000 households, the ministry said. Delphine Batho, the environment minister, said it would also make France a pioneer in Europe in preventing light pollution, which disrupts ecosystems and people's sleep patterns. The move has prompted some, especially in Paris, to worry that the government's new proposal could harm tourism.