The judge at the Conseil d'Etat ruled that the "imminent danger justifying the state of emergency has not disappeared, given the ongoing terrorist threat and the risk of attacks", according to a statement issued by the court.
The decision echoed arguments put forward in court by the interior ministry to keep the state of emergency in place, after the French Human Rights League (LDH) on Tuesday asked the court to suspend all or at least some of the measures.
President Francois Hollande is set to seek parliamentary approval to extend the current three-month state of emergency, which expires on February 26.
The Senate is to vote on the proposal on February 9, followed by a vote in the National Assembly on February 16.
Concern has been growing in recent weeks about the state of emergency, which was introduced after coordinated gun and bomb attacks left 130 dead in Paris on November 13.
The measures boost police powers, allowing house arrests, raids both day and night and the banning of public gatherings, without permission from a judge.
The Council of Europe's human rights commissioner Nils Muiznieks warned this month that the measures could constitute a "threat" to democracy. He notably raised concerns about the ethnic profiling of suspects facing police searches.
And a panel of UN human rights experts said the measures placed what they saw as "excessive and disproportionate" restrictions on key rights.