Paris, France (CNN) -- French Labor Minister Eric Woerth will be questioned by police as part of an investigation into the finances of France's richest woman, a spokeswoman for the prosecutor's office said Wednesday.
No date has been set for the questioning, she said.
Woerth's wife, Florence, was already being questioned Wednesday, the spokeswoman said. Secret recordings published last month revealed that she was, until late June, the deputy to the financial adviser of L'Oreal heiress Liliane Bettencourt.
The questioning follows allegations that Bettencourt made illegal cash payments to French President Nicolas Sarkozy, including some that were handed over to Woerth.
Woerth and Sarkozy have both denied the allegations.
The claims originated in the secret recordings, allegedly made by Bettencourt's butler, of conversations between the heiress and her financial adviser, Patrice de Maistre.
Bettencourt's former bookkeeper, Claire Thibout, elaborated on the allegations in an interview this month with a French investigative website. She said she prepared envelopes of cash that were to be given to Sarkozy and Woerth, who previously worked in the Budget Ministry and was in charge of reforms to France's retirement system.
Thibout's lawyer told French news agency Agence France-Presse this month that de Maistre once asked his client for 150,000 euros ($188,800) and said he would give it "discreetly" to Woerth at a dinner.
Thibout testified before a judge about the allegations last week. Wednesday, French newspaper Le Monde published her testimony, in which she repeated her allegations against de Maistre and said she regularly withdrew large sums of money at his request.
Among other claims is that Sarkozy's 2007 presidential campaign received money from Bettencourt in excess of campaign finance limits.
The secret recordings also refer to a bank account in Switzerland containing 80 million euros ($98.3 million), which had not been reported on Bettencourt's taxes.
CNN's Saskya Vandoorne contributed to this report.