Organisers of the 2023 Rugby World Cup in France said police raided their offices Wednesday as part of a legal probe into the management of the competition under former chief executive Claude Atcher.

Atcher was sacked as head of France-2023 last month after an internal investigation reported "alarming managerial practices" amid allegations of bullying and harassment from staff.

The national financial crimes prosecutor's office confirmed Wednesday for the first time that it had opened an investigation into possible favouritism, corruption and influence-peddling at France-2023, which is structured as a public-interest group.

The probe followed a referral from auditors at the finance and sports ministries, the prosecutor's office said in a statement that confirmed raids were underway at different locations.

"This intervention follows on the inquiry of the finance inspectors, tasked by the government this summer with verifying the management of the organising committee units," France-2023 said in a statement, adding that it would not comment further for the time being.

France's sports daily L'Equipe said investigators were looking into the misuse of personal expenses, "certain contracts in the past and also alleged irregularities linked to the ticketing system for the 2023 World Cup."

Atcher's suspension was prompted by the preliminary findings of a Labour Inspectorate investigation launched at the end of June, after L'Equipe reported accusations of his "management by terror."

Atcher's deputy Julien Collette took over from him as chief executive.

The Rugby World Cup kicks off on September 8 next year with hosts France playing New Zealand at the Stade de France.

The final is scheduled for October 28.

The dysfunctions in the World Cup organising committee are an unwelcome embarrassment for France as it prepares to host the Olympics in 2024.

In September, French prosecutors demanded prison time for Bernard Laporte, head of the French Rugby Federation (FFR) and a former sports minister, on charges of corruption and influence-peddling.

At the same trial prosecutors called for Atcher to receive a two year prison sentence, with one suspended.

The charges relate to business deals struck with Mohed Altrad, the billionaire businessman and owner of Top 14 champions Montpellier, including a contract to put Altrad's corporate logo on the French national team's jerseys.

Laporte denied the claims during the trial that closed for deliberation in September, with a ruling still awaited.