David Vautier, 22, currently residing on the French warship Duquesne, admitted injuring Luke Farrugia in the face during a fight in Paceville.
Another man residing on the ship was also charged in court along with Vautier.
French national Sebastian Camilleri, 25, admitted carrying an unlicensed weapon on the night in question. He was ordered to pay a Lm60 fine. Both men also pleaded guilty to the charge of breaching the peace by being rowdy.
“This was a silly incident that could have had serious consequences, especially for such young men,” said Magistrate Jacqueline Padovani Grima after handing down the judgement. “I hope you have learned your lesson,” she said pointedly.