The men were in high spirits despite their defeat in Saturday's game, which saw Belgium beat Ireland 3-0.
The clip, recorded on a mobile phone, starts with the crowd singing the Frankie Valli lyrics: "You're just too good to be true, can't take my eyes off of you".
Several fans even get down on one knee and extend a heartfelt arm in tribute to her.
As the song hits the climactic chorus, Miss Roméra takes out her phone and starts filming the crooning crowd.
Miss Roméra can be seen covering her mouth and laughs as she slowly spins around to take in the spectacle. Then the crowd starts shushing as murmurs of 'speech, speech' are heard - but the sports lovers change their minds and instead launch into a lively rendition of DJ Otzi's 2000 pop hit Hey Baby.
One of the men even swoops in to give her a quick kiss on the cheek.
The crowd then start whooping in anticipation as she prepares to kiss the guy standing opposite her. Miss Roméra turns to speak to her friend in French - then turns back and pecks the man on the cheek, as the crowd erupts in cheers around them.
The footage was uploaded on Facebook on Saturday and has been viewed more than one million times.
One viewer commented: 'This is brilliant', while another added: 'Such a beautiful ending!'
The Irish supporters were clearly in jubilant spirits, and were also filmed serenading the French gendarmes. A video showed hundreds of dancing fans singing the Pet Shop Boys' hit Go West, but replacing the chorus with "stand up for the French police".