Thieves stole nearly €4 million ($4.57 million) worth of crystal jewelry from the Lalique Museum in northeastern France during a burglary on Sunday, according to French media reports.
Authorities said several masked suspects forced open a door, smashed six display cases and escaped with 20 pieces of jewelry.
The museum has been closed until further notice while officials assess the damage and review security measures.
In a statement, the museum said the gendarmerie had responded to the incident and an investigation was underway.
Wingen-sur-Moder Mayor Christian Dorschner said the suspects appeared to have specifically targeted the jewelry collection. He also said the museum’s alarm system functioned properly, but the security company did not immediately notify police.