Zurich - FIFA on Thursday immediately suspended secretary general Jerome Valcke over misconduct allegations and put him under investigation.
Valcke "has been put on leave and released from his duties effective immediately until further notice," said a FIFA statement.
"Further, FIFA has been made aware of a series of allegations involving the secretary general and has requested a formal investigation by the FIFA Ethics Committee."
The allegations, denied by 54-year-old Valcke, have been made by a consultant at a company that struck a deal with FIFA to sell tickets for the 2014 World Cup but the contract was cancelled.
The Frenchman, who has been FIFA president Sepp Blatter's right-hand man since 2007, is alleged to be the beneficiary of an agreement to sell the tickets at inflated prices.
FIFA have been embroiled in a major corruption scandal since the arrest of seven of its officials on May 27 attending a FIFA congress in Zurich to elect a new president.
They are among 14 people charged by US authorities over more than $150 million in bribes given for television and marketing deals.
Despite the arrests in May the election went ahead with Blatter winning a fifth mandate although he then announced he would be standing down with a new election scheduled for February.
Valcke was not implicated in the FIFA corruption scandal although he has been a steadfast supporter of Blatter.