A review of the court records by The New York Times indicates that Ikea’s investigations were conducted for various reasons, including the vetting of job applicants, efforts to build cases against employees accused of wrongdoing, and even attempts to undermine the arguments of consumers bringing complaints against the company. The going rate charged by the private investigators was 80 to 180 euros, or $110 to $247, per inquiry, court documents show. Between 2002 and 2012, the finance department of Ikea France approved more than €475,000 in invoices from investigators.

The case has caused public outrage in France, not only because of the company’s large consumer following in this country — Ikea’s third-largest market after Germany and the United States — but because the spying cases occurred in a country that, in the digital age, has elevated privacy to a level nearly equal to the national trinity of Liberté, Égalité and Fraternité.

So far, there have been no accusations that such surveillance occurred in any of the other 42 countries in which Ikea operates, and it remains unclear why the French Ikea unit is purported to have engaged in it so extensively. Very little of the surveillance yielded information Ikea was able to use against the targets of the data sweeps. But court documents indicate that investigators suspect that Ikea may have occasionally used knowledge of personal information to quell workplace grievances or to prompt a resignation.

“It is hard to conceive that this kind of thing happens in a democratic society like France,” said Sofiane Hakiki, a lawyer representing Ms. Paulin and several unions that have filed civil complaints against Ikea in the affair. “This is not Soviet Russia.”

The company, which the court required to post a bond of €500,000 euros last month, conducted its own review of the matter last year, after a series of internal emails detailing spying were leaked to the French news media. That internal inquiry resulted in the firing of several executives, including the former chief executive, Jean-Louis Baillot. But Ikea has otherwise declined to comment publicly on specifics of the claims.