French tennis player Mathieu Montcourt died on Monday night at the age of 24, the French Tennis Federation said on Tuesday.
It said the cause of death was unknown.
The French Tennis Federation said Montcourt, who was 119th in the ATP world rankings, was a popular figure.
"Mathieu was an enthusiastic and passionate young man, who was very engaging and extremely well-liked because of his kindness and politeness," it said in a statement.
Montcourt had just begun a five-week ban
Montcourt was originally banned for eight weeks in August last year by the governing body of men's tennis (ATP) but this was reduced by the Court of Arbitration for Sport (CAS) in May.
CAS upheld a $12,000 fine imposed by the ATP, a punishment Montcourt said was "ridiculous" as he had gambled small sums in 2005 that added up to a total of only $192 and that the rules covering gambling were unclear.