Border controls are being implemented, it does not appear that borders are being closed (at least at airports).
“The President of the Republic has decided to immediately institute systematic controls at entry points into the country,” the French government said in a statement. “These checks are to be carried out at road crossings, rail, sea, and airports. Airports continue to operate.”...
Above from
France Implements Border Controls, Declares State of Emergency Following Attacks Killing More than 100
Above appeared in FBT, where I serve as ed.dir.