The French National Prosecutor's office said that prosecutors began interrogating Laporte yesterday morning as part of a preliminary investigation into suspicions of laundering tax fraud proceeds.

The probe dates back to August 2020.

Laporte's lawyer Jean-Pierre Versini-Campinchi confirmed that Laporte had been released, and said that he had not been accused of being a beneficiary in the case.

"It is a case in which he is implicated for having been associated with rugby friends a long time ago," Versini-Campinchi told the Agence France-Presse (AFP) news agency.

"He has neither been accused of having defrauded nor of having received any money."

French newspaper L'Équipe has reported that two other people were taken into custody.

This case is separate to Laporte's conviction of corruption, bribery and influence peddling charges last month, for which he was handed a two-year suspended prison sentence.

He "self-suspended" himself as World Rugby vice-chair and temporary stood down as head of the FFR, but has vowed to appeal and continues to protest his innocence.

His two-year ban from any position in the sport is not immediately enforceable because of the expected appeal.

A total of 1,941 French rugby clubs have until tomorrow to vote on approving FFR Deputy President Patrick Buisson as Acting President.

Laporte had initially refused to resigned, but opted to stand down temporarily after coming under pressure from his organisation's own Ethics Committee and French Sports Minister Amélie Oudéa-Castéra.

Florian Grill, who narrowly lost to Laporte in the 2020 FFR Presidential election, has criticised the choice of Buisson - who was selected by Laporte - as Acting President and urged clubs to vote against his appointment.

Grill wants fresh elections to be held.

The timing of Laporte's detainment in the tax fraud investigation was criticised by Versini-Campinchi.

"It is perfectly scandalous that the prosecutors have chosen the date of Patrick Buisson's election for the questioning and that the disclosure of this questioning was made on the same day," the lawyer told AFP.

French rugby has been plunged into crisis with the country set to host the men's Rugby World Cup from September 8 to October 28 this year.

Financial prosecutors searched the Organising Committee's headquarters as part of a Government inquiry into its management in November.

France is also due to begin the defence of its Six Nations Championship crown next month, and rugby sevens is on the programme for next year's Olympic Games in Paris.