PSG fans were seen wearing the green and white colours of the Scottish Premiership champions during their Champions League quarter-final clash with Aston Villa.
One supporter was pictured in a Celtic-themed balaclava, while another held a scarf with the words 'Celtic Ultras' aloft.
The connection between the French club and the Glasgow side is not known at this moment in time, but it is clear that the Hoops have some fans in Paris.
Their presence at the stadium comes after Villa Park was decked out in green and white for Celtic's visit back in January in the UCL phase.
Despite losing the match, PSG secured their place in the semi-finals of the competition with a 5-4 aggregate victory.
John McGinn scored for Villa, but it wasn't enough as Unai Emery's men crashed out.