The ex-Chelsea and Milan star took a video of himself singing Celtic’s pre-match anthem You’ll Never Walk Alone before letting off a hearty laugh.
Desailly was at the game to help cover the match for French television. PSG ran out 5-0 winners.
Earlier in the day, the 49-year-old visited Ibrox to honour the time he played against Rangers in the Champions League group stage.
Desailly was part of the Marseille side which drew 2-2 with Walter Smith’s men in the 1992/93 campaign. The French side would go on to win the competition after beating Milan in the final.