Former UEFA president Michel Platini denied wrongdoing during police questioning on Tuesday following his arrest as part of a corruption probe into the vote that gave the 2022 World Cup to Qatar.
Platini, a former France football great, can either be released or formally charged after questioning ends.
His communications team said he was also quizzed on the awarding of the 2016 European Championship to France, adding that he was "absolutely confident in the future" and has "strictly nothing to reproach himself with."
"Michel Platini expresses himself serenely and precisely, answering all the questions, including those on the conditions for the awarding of the 2016 Euro, and has provided useful explanations," the statement said.
Platini's lawyer, William Bourdon, said the former Juventus playmaker was also questioned as a witness and placed in custody only for "technical reasons."
He explained that by holding him in custody, police investigators aimed to ensure Platini and other witnesses couldn't confer with each other about their testimonies.
Former FIFA president Sepp Blatter, who has been a criminal suspect since September 2015 but never charged, told The Associated Press he has "part of my trust and confidence in the Swiss justice back."
Frenchman Platini was detained and taken to the premises of the Anti-Corruption Office of the Judicial Police (OCLCIFF).
Also detained on Tuesday for questioning was Sophie Dion, a former sports adviser of Nicolas Sarkozy when he was French president, a judicial official said.
Claude Gueant, the former secretary general of the Elysee under Sarkozy, was quizzed by investigators as a witness and not detained.
French financial prosecutors have been investigating the bidding process for the 2018 and 2022 World Cups and previously questioned former FIFA president Sepp Blatter.
FIFA said it is "concerning" to hear that former UEFA president Michel Platini has been arrested in France in relation to a corruption probe.
The governing body says it is aware of the reports concerning Platini but does not have the details of the French investigation.
As UEFA president, Platini was also a FIFA vice president.
FIFA says it "reiterates its full commitment to cooperating with the authorities in any given country of the world where investigations are taking place in connection with football activities."
France's financial prosecutor services opened the investigation on grounds of private corruption, criminal association, influence peddling and benefiting from influence peddling relating to the 2018 and 2022 World Cups, which were awarded to Russia and Qatar respectively.
Platini's lawyer and adviser did not immediately answer messages for comment from The Associated Press (AP).
Much intrigue has centered on Platini's decision to vote for Qatar.
Blatter, who was FIFA president at the time of the vote in 2010, blamed Platini for backing out of a secret "gentleman's agreement" to award the 2022 tournament to the United States.
Platini told the AP in 2015 that he "might have told" American officials that he would vote for the United States bid.
However, he changed his mind after a November 2010 meeting, hosted by then-President Nicolas Sarkozy at his official residence in Paris and Qatar's crown prince, now Emir, Tamin bin Hamad al-Thani.
Platini has long insisted that the meeting did not influence his vote for Qatar less than two weeks later.
"Sarkozy never asked me to vote for Qatar, but I knew what would be good," he told the AP in 2015.
But Blatter claimed in a 2015 interview with the Financial Times that Platini told him ahead of the World Cup vote: "I am no longer in your picture because I have been told by the head of state that we should consider the situation of France."
Both Platini and Blatter were toppled from their positions of power at the top of soccer in 2015.
Platini was banned by FIFA for financial misconduct in relation to a $2 million payment authorized by Blatter - a suspension due to expire in October.
Qatar's methods to bring the World Cup to the Middle East for the first time have been subject to investigations by FIFA.
American attorney Michael Garcia found that some of Qatar's conduct "may not have met the standards" required by FIFA but concluded there was no "evidence of any improper activity by the bid team."
The World Cup, normally held over the summer, was moved to winter to avoid the extreme heat in Qatar, which can reach highs of 45C (113F).
Questions have long been raised over the Gulf State's suitability to host the World Cup.
Critics have argued the country is too small to host such a large-scale event while others have also argued the country's human rights record should have disqualified the bid.