At least two stolen paintings were abandoned amid a getaway, an official said.
The Louvre Museum's director resigned Tuesday, ending months of questions in France's cultural world over why no top official had stepped down after the October crown jewels theft.
The Underground Railroad was a secret pathway to freedom for enslaved people escaping north, through woods, tunnels, private homes, under floorboards, inside churches and even hidden beneath wagons.
When thieves broke into the Louvre and cut through display cases, they seized a trove of Napoleonic jewels. But in their escape, the crown of Empress Eugénie slipped from their grasp and was left battered on the pavement below.
Under the new structure, visitors who are neither citizens nor residents of the EU will pay the higher rate, the Louvre said.
An official said 30 seconds could have made the difference in the October heist.