From the BBC:

The Eiffel Tower stands in darkness after its spotlights are switched off
National consumption fell by over 1% during the switch-off

The lights of Paris dimmed for five minutes on Thursday in a nationwide "lights out" campaign, aimed at raising public awareness over global warming.

The Eiffel Tower, lit by 20,000 bulbs, also went dark at 1955 (1855 GMT).

During the switch-off, the power grid operator RTE observed a fall of 800 megawatts, representing just over 1% of France's total consumption.

It comes a day before the release in Paris of a major report warning of humanity's role in climate change. ...

Environmental campaigner Anne Briangault told the BBC that people would like to be involved in tackling climate change but needed advice on what they could do.

"... we are explaining they can do things, they can switch off some lights but it's not enough. Politicians have to make actions too," she said from the base of the Eiffel Tower.