Detectives were scouring video camera footage from around the Louvre as well as of main highways out of Paris for signs of the four robbers, who escaped on scooters.
But she is seen as socially conservative, opposing revising a 19th-century law requiring married couples to share the same surname, and wants the imperial family to stick to male-only succession.
Moscow doused hopes of a swift meeting of the Russian and US foreign ministers to prepare for a speedy summit between their leaders over the Ukraine war.