0230 GMT February 19, 2020
Hundreds of tourists were confined to secure areas of the world-famous art gallery in central Paris after the attacker was shot five times around 10:00 (1100 GMT) in a public area inside the complex, AFP reported.
Prime Minister Bernard Cazeneuve called the attack "terrorist in nature".
One soldier was "lightly injured" and has been taken to hospital, while the knifeman is in a serious condition but is still alive, security forces said.
Two backpacks carried by the assailant were checked by bomb disposal specialists at the scene and were found not to contain explosives.
The incident sparked fresh jitters in a country still reeling from a string of terror attacks over the last two years and under a state of emergency since November 2015.
Thousands of troops have been deployed to guard the capital, with groups of soldiers with automatic rifles a regular sight inside the Louvre and around its sculpture-filled gardens.
The huge former royal palace in the heart of the city is home to the Mona Lisa and other renowned works of art but also a shopping area and numerous exhibition spaces.
The attacker was shot in a shopping area that leads to the museum.
"The people who were in the museum – there were about 250 of them – were held at a distance and confined in secure areas of the Louvre," Police Chief Michel Cadot told reporters outside.
A second man whose behavior was "suspicious" has been arrested, Cadot said, without giving further details.
String of attacks
France has suffered a string of attacks in recent years, beginning in January 2015 when gunmen killed journalists at the Charlie Hebdo satirical newspaper in Paris.
Another attacker went on to kill shoppers in a supermarket, with a total of 17 people dead in three days of bloodshed.
Ten months later, gunmen and suicide bombers from the Daesh group attacked bars, restaurants, a concert hall and the national stadium in Paris on November 13, 2015, killing 130 people.
And last July, a Tunisian rammed a lorry through crowds celebrating Bastille Day in Nice on France's south coast, crushing 86 people to death.
The Louvre was already suffering from a fall in visitor numbers after the series of attacks in France.
Over the last two years, numbers are down about two million, casting doubt on its claim to be the most visited museum in the world.
Last year, there was a 15-percent slump in visitors compared to 2015, to around 7.3 million.