A group of masked robbers broke into the French home of a family and, during an overnight ordeal, forced them to transfer 40,000 euros ($46,000) in cryptocurrency, a local prosecutor said Sunday.
The family -- a couple and their two children, aged 8 and 12 -- had to be treated by paramedics for shock after the robbers left their home in Vendin le Vieil, a village on the outskirts of the northern city of Lens.
Police were hunting the gang of four criminals who carried out the robbery, prosecutor Etienne Thieffry said.
The father in the family worked in the technology sector, the prosecutor said.
France has in the past couple of years experienced an wave of robberies targeting owners of cryptocurrency, which is stored digitally and whose ownership and transfer is difficult or impossible to trace.
In the first six months of this year, 77 such crimes were recorded, a significant jump on the same period last year.
Interior Minister Laurent Nunez in June vowed to boost security for people working in the crypto sector.