Around 2,000 gold and silver coins worth around €90,000 (£78,000; $104,000) were stolen during a raid at another French museum - just hours after the audacious theft of some of the French crown jewels at the Louvre in Paris.
The incident happened at a museum dedicated to French philosopher Denis Diderot in Landres, north-eastern France, on Sunday night.
When the Maison des Lumières (House of Enlightenment) opened on Tuesday, workers noticed a smashed display case and raised the alarm, officials said. The coins were selected with great expertise, a statement to French media from the local authority said.
It is the latest in a recent string of heists at cultural institutions across France.
The stolen coins date from between 1790 and 1840 and are part of the city's private collection, discovered in 2011 during renovation work at the museum, according to local media.
Last month, criminals broke into Paris's Natural History Museum, making off with six gold nuggets worth around €1.5m. A Chinese national was arrested in Barcelona in connection with this raid while trying to dispose of some melted down gold, according to prosecutors. She was charged earlier this month and is being held in pre-trial detention.
Also in September, thieves stole two Chinese porcelain dishes and a vase with an estimated combined worth of €6.55m from the national porcelain museum in the central city of Limoges. The items are still missing and no arrests have been made.
Art detective Arthur Brand warned that museums across Europe could see a flurry of copycat raids in the coming months, particularly after the high-profile theft of crown jewels from the Louvre.
Security measures at such cultural institutions are being called into question, as both the Louvre and Natural History Museum have suffered significant losses due to apparent vulnerabilities in their protection protocols.
