Conor McGregor will face no action over an allegation of sexual assault in Corsica last year.

The UFC star was arrested last September and questioned over an alleged incident during which he was alleged to have exposed himself to a young married woman as she entered a bar toilet.

The alleged victim has claimed the 32-year-old Irishman showed off his manhood and then assaulted her following a heavy drinking session in the upmarket port town of Calvi on September 6.

McGregor "vigorously denied" the accusations at the time and now police have confirmed they uncovered no evidence of assault despite ordering a battery of scientific tests.

A statement from Basta prosecutor Arnaud Viornery read: "We had no material evidence to corroborate the complainant's statements, including after the scientific expert input that had been ordered."

Conor McGregor will face no further action
Conor McGregor will face no further action

McGregor's lawyer, Emmanuelle Ramond, said: "We welcome this decision because it is in line with what we expected."

McGregor had been staying on his yacht in Corsica with his girlfriend, Dee Devlin, and their two children.

He had been preparing to take part in a 180-kilometer, 24-hour charity water bike race from Calvi to Monaco alongside Princess Charlene of Monaco but he was forced to withdraw.

McGregor is currently preparing for his third fight with Dustin Poirier after signing the bout contract yesterday.

The trilogy clash will take place on July 10 in Las Vegas in front of a capacity 20,000 crowd at the T-Mobile Arena.

The rivals met in January with Poirier winning by second-round stoppage, six years after losing his first fight with McGregor in the opening round.

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Poirier had the option of fighting for the vacant lightweight title next month but instead opted for the more lucrative option of a third fight with McGregor.

Charles Oliveia and Michael Chandler will meet for the 155lb belt on May 15 with the winners of both fights expected to meet later this year.

Earlier this week, McGregor threatened to pull out of his fight after Poirier went public with an accusation that his rival had failed to follow through with a $500,000 donation.

McGregor had promised to make the payment to help build a gym through Poirier's foundation but has yet to write a cheque.

The Dubliner claimed he was waiting to be told how his money would be spent before launching a furious tirade at Poirier.

Ultimately, however, he agreed to proceed with the fight while Poirier apologised for taking the row to social media.