Here's what we know ... a person filed a complaint against McGregor on Thursday, Sept. 10 -- accusing him of "attempted sexual assault and sexual exhibition," according to prosecutors.
A spokesperson for the prosecutor's office later issued a statement saying McGregor was "arrested and placed in custody by the judicial authorities."
"He was released on Saturday."
Reps for McGregor insist NO CHARGES have been filed against Conor at this point -- and he adamantly denies the allegations against him.
Officials have not released details about the allegations -- but France 3 Corse (local TV network) is reporting McGregor "exhibited his private parts to [a young woman] without her consent as she made her way into the bar restroom" on Sept. 6.
McGregor's manager, Audie Attar,issued a statement to MMA Fighting, saying, "I am irate and putting out a warning loud and clear: Conor McGregor is not and will not be a target for those seeking to score a headline or a payday," suggesting the whole thing is a shameless attempt at a payday.