Fulham boss Hughes: Dembele has been personal long-term target
Hughes was aware of the 23-year-old when he was Manchester City manager and reacted immediately when he learnt of his availability.
"Moussa is always very positive, everything he does has a positive slant on it. That's the key to the way he plays," he said.
"He can drive the game and is an intelligent footballer.
"I kept track of him because I've always been impressed with him.
"When it was flagged up that he was in the last year of his contract and likely to be sold, we moved quickly."