French Rugby Federation (FFR) president Bernard Laporte was released without charge on Tuesday after being detained earlier in the day as part of an investigation into suspected tax fraud.
Financial prosecutors, who had announced his detainment, and one of Laporte's lawyers confirmed his release.
"It is a case in which he is implicated for having been associated with rugby friends a long time ago," the lawyer, Jean-Pierre Versini-Campinchi, told AFP.
"He has neither been accused of having defrauded nor of having received any money."
Earlier this month, Laporte stepped back from his role at the FFR without resigning after being convicted of unrelated corruption charges nine months before France hosts the Rugby World Cup.
The most recent investigation dates back to August 2020.
Tuesday's incident comes as the almost 2,000 French rugby clubs are voting on whether to accept Laporte's appointed interim president Patrick Buisson, with the results expected on Thursday
"He was summoned for questioning by tax authorities, he went there with a lawyer specialising in tax," said 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," he added.
Former France head coach Laporte, who has been in office since 2016, was found guilty on 13 December of five of the six offences for which he was prosecuted, including corruption and favouritism.
Laporte, 58, received a two-year suspended prison sentence.
He was also banned from holding any rugby post for two years, but this is suspended pending his appeal.
In the wake of his conviction, Laporte stepped down from his role as vice-chairman of the sport's global governing body, World Rugby, pending a review by its ethics officer.
On 5 February, Les Bleus start the defence of their Six Nations title with a trip to Italy and they are looking to extend a national record of 13 straight Test wins.
The Rugby World Cup, the sport's global showpiece event, then kicks off in Paris on 8 September.