A number of arrests have been made at Ikea France over allegations the European arm of the Swedish family business hired a security firm to spy on employees and customers using police files.
Ikea France is being investigated as a corporate entity, and could be forced to pay compensation to any victims of spying.
Stefan Vanoverbeke, chief executive of the French division of the Swedish flat pack furniture business, along with his predecessor Jean-Louis Baillot, and chief financial officer Dariusz Rychert were arrested on Monday.
They are accused of using police files and hiring a firm of private detectives to obtain information on staff, job applicants and dissatisfied customers.
Four police officers and Ikea's former head of security have also been arrested.
Two unions have filed complaints against the company, accusing Ikea of spying on hundreds of employees over a five-year period.
The investigation was launched in February last year after satirical magazine Le Canard Enchaine published email chains allegedly between the accused and security firm Surete International.
Le Canard Enchaine said Ikea paid the firm €80 for each request for information, which it pooled from police databases, and that up to 200 demands were made on each occasion.
Following the fallout from the magazine's revelations, Ikea France fired three senior directors and its head of risk management, and it has since put in place a new code of conduct.
Ikea, controlled by the Kamprad family, had revenues of €27.6 billion in 2012, and France is one of their largest European markets – it has almost 26 stores in the country, with 9,300 employees.
Roberto Monti, Ikea's director for southern and eastern Europe, said in a statement he had complete confidence in all of the directors implicated, and said Ikea France was cooperating with the investigations.