PARIS (AP) — A freight lift rose up on its crane Tuesday toward the Louvre Museum — but this time it wasn’t jewel thieves. It was workers installing security bars on the window used to break into the Paris landmark’s Apollo Gallery in October’s stunning heist.

The world’s most-visited museum is slowly coming to terms with security failings exposed by the theft, while investigators hunt for missing crown jewels worth $102 million.

With the Louvre closed Tuesday, maintenance workers in security helmets and high-visibility vests mounted a freight lift to a second-floor balcony to secure new metal bars outside a now-infamous window.

The sight mirrored what happened Oct. 19, when a team of thieves posing as workers used a similar lift, then sliced through the window to enter the gallery. They grabbed tiaras, emerald earrings, a sapphire necklace and other treasures, and eight minutes later they were gone.

All four suspected thieves have been arrested and charged. But the jewels haven’t been found.

Samuel Lasnel of maintenance lift company Grima-Nacelles said he and his crew arrived before dawn Tuesday to carry out the high-profile window-securing operation.

“We have already worked at the Louvre — on the interior, on the exterior, inside and outside the pyramid — we’ve been here several times,” he told The Associated Press. “The Louvre knows us well.”

The Louvre didn’t publicly comment about Tuesday’s security operation.