"C'est peut-être lui."
Traduction :It is possibly him.
(Please excuse my English). That does not sound right to a native speaker. The repetition of 'is' and the 'be' in 'maybe' sounds odd, even though that is what happens in the French phrase.
“It may be him” or “It might be him” are the best translations I feel. And notice that we make ‘may be’ two separate words in this context.