Paris police: Security operation under way near Notre Dame
Paris police say a security operation is under way near Notre Dame Cathedral and are urging passers-by to stay away from the area.
The police department tweeted about the operation on Tuesday afternoon but did not provide any details.
A police official would not provide further information.
Large numbers of police cars filled the area on the Ile de Cite island in the River Seine in the centre of Paris.
Paris is under high security after a string of Islamic extremist attacks in recent years.