The 23-year-old has been strongly linked with a January move to Premier League giants Manchester United.
The midfielder dubbed ‘the new Zidane’, has been in excellent form for Montpellier this season.
Fernandez told Reuters: “He is an intelligent boy who is enjoying a good season.
“Now, if in the winter transfer window Manchester United offer €18m (£15m) as I have read, he must go.
“Although that would kill the team, one cannot refuse an offer like that.”