Emmanuel Macron also asked his government to prepare draft legislation to reinforce security measures permanently beyond the state of emergency, the announcement on Wednesday said.
If approved by parliament, it would be the sixth such extension. Human rights groups have previously raised concerns over the emergency rule, arguing that it diminishes civil liberties.
The move comes as Macron, who was elected in a May 7 vote, settles into office, and follows an attack in neighboring Britain two days earlier.
On Monday, a suicide bomber in the northern city of Manchester detonated his vest at a concert arena after a performance by the American pop star Ariana Grande, killing at least 23 people, including himself.
France has been in a state of emergency, which gives sweeping powers to the police, since November 2015, when at least 130 people were killed in coordinated attacks.
The country has suffered several attacks since then, including a truck-ramming assault that killed at least 86 people in Nice last year.
Macron made the decision after a security meeting on Wednesday in which top officials "studied the implications of this new terrorist attack on measures of protection to ensure the security of our compatriots," Al Jazeera reported.