UN climate conference: France to impose border controls
France will impose border controls for one month from 30 November for the UN Conference on Climate Change in Paris.
French Interior Minister Bernard Cazeneuve said it was a precaution "because of the terrorist threat or risk of public disorder".
"It is by no means a suspension of Schengen," he stressed, referring to the EU free travel zone where passport checks are minimal or non-existent.
Schengen rules allow countries to restore border controls temporarily.
France reinstated border controls in 2011 for a G20 summit in Cannes, attended by many world leaders.
Anti-globalisation protests are a feature of the G20 summits and similar gatherings of leading industrialised nations.
France is especially conscious of the terrorist threat after January's jihadist attacks in Paris. Seventeen people died when gunmen targeted Charlie Hebdo magazine staff, police officers and a Jewish supermarket.
In December 2009 Denmark - a member of Schengen - imposed temporary border checks when it hosted the UN Climate Change Conference in Copenhagen.
The Schengen zone has 26 members - that is, most EU countries plus four non-EU members.
The Paris climate change talks will be held from 30 November to 11 December at Le Bourget, in the city's north-eastern suburbs.
The aim is to agree on new targets to reduce carbon emissions and prevent global warming, amid fears that increasing volumes of greenhouse gases could irreversibly harm the planet.
US President Barack Obama and Chinese President Xi Jinping will be among more than 80 world leaders attending the opening.
Speaking on Friday, France's interior minister insisted that the decision to reimpose border controls was not linked to Europe's current migrant crisis.
The EU is struggling with an unprecedented influx of migrants - many of them Syrian refugees - seeking asylum in northern Europe. Greece and Italy are the main entry points, and their reception centres are overwhelmed with the numbers.