Prosecutors in Versailles near Paris on Thursday opened an investigation into the affair following a complaint from a trade union and a report in satirical weekly Le Canard Enchaine.
Ikea also said it would examine claims that the firm paid for illegal access to secret French police files in order to gain information about its employees, clients and even people who came near its property, Ikea said.
Le Canard published what it said were email exchanges between the head of the company's risk management department, Jean-Francois Paris, and Yann Messian of Surete International about getting access to the police force's STIC files.
The controversial STIC file system has been criticised for being an unreliable database of millions of names and personal information about crime perpetrators, victims and even witnesses.
The newspaper said that Surete International offered access to the files for €80 ($101) a time, as well as to a database of vehicle owners.
The report quoted emails requesting information on employees, including union members, on the names associated with a list of mobile phone numbers and asking to know who were the owners of certain car registrations.
A statement sent to AFP on Saturday said the former management of Surete International, which was wound up in 2011, denied responsibility for everything attributed to it.
The statement said the employee cited by the Canard Enchaine had already been informed of his dismissal for lack of results and disloyalty when he used Surete International's email address to make an "illicit proposal" to Ikea's risk manager on behalf of another company run by a friend.
"Any proposal or contract he might have made as commercial director would have been without the knowledge of his own management," it said, while claiming the Ikea had not followed up the contact.
Surete International's former boss Christophe Naudin told AFP the company had worked with Ikea in an advisory capacity since 1998 "but not for this type of inquiry".
Messian for his part denied being behind any misuse of the STIC files, telling the rue89 website he had only "repeated something that Christophe Naudin told me", without elaborating.