The Louvre Museum in Paris and Versailles Palace evacuated visitors and staff Saturday after receiving bomb threats. The government has put France on high security alert after a fatal school stabbing by a suspected extremist.

The Louvre communication service said no one was hurt and no incident was reported. Paris police said officers searched the museum after it received written bomb threats.

The former royal palace at Versailles also received bomb threats, a national police spokesperson said.

The palace and its sprawling gardens were being evacuated while police examine the area, the spokesperson said.

Alarms rang out through the Louvre, a vast space also in a former royal palace Paris overlooking the Seine River, when the evacuation was announced, and in the underground shopping centre beneath its signature pyramid.

Police cordoned off the monument from all sides, and the underground access, as tourists and other visitors streamed out.

Videos posted online showed people leaving, some hurriedly and some stopping to take photos, others apparently confused about what was happening.

The French government raised the threat alert level and is deploying 7,000 troops to increase security after Friday's school attack.

French authorities say a former student suspected of Islamic radicalisation killed a teacher and wounded three other people before being captured.

The government is also concerned about fallout in France from the war between Israel and Hamas.

The Louvre, home to masterpieces such as the Mona Lisa, welcomes between 30,000 and 40,000 visitors per day.