French Interior Minister Bernard Cazeneuve Tuesday said Paris was deploying 1,600 additional police to border crossings and air, sea and rail infrastructure after the Brussels attacks which killed at least 21 people.
"Access to public transport will be restricted to people with tickets and/or ID cards," and they may be frisked, he said after a meeting with President Francois Hollande.
Cazeneuve also called on Europe to "further boost coordination and the fight" against terrorism.
"These events that strike at the heart of Europe... show the need to reinforce even more the fight against terrorism," he said.
The minister said French authorities have already prevented 10,000 people from entering the country since the November attacks in Paris that claimed 130 lives.