The world No.31 returned from a 10-minute heat break in her match against Swede Johanna Larsson at the US Open and realised she had put her top on back to front - but turned it round in a matter of seconds.
But the French player was immediately hit with a code violation for her actions from the umpire.
And the call has sparked a barrage of criticism on social media.
Judy Murray, mother of former world No.1 Andy Murray, highlighted on Twitter that men were allowed to change their shirts on court.
She wrote: "Alize Cornet came back to court after 10 minute heat break. Had her fresh shirt on back to front. Changed at back of court. Got a code violation. Unsportsmanlike conduct... But the men can change shirts on court."
Retired Australian tennis star Casey Dellacqua tweeted it was "ridiculous."