Kandol scored 13 times in 17 outings for the Bees this season before moving to Leeds in November, where he has netted only once in nine appearances.
Kandol's former club Dagenham, whom Barnet paid £50k a year ago, will also receive money from the deal thanks to a sell-on clause
"We wish to thank Tresor for his services to Barnet, and we wish him the best of luck for the future," Bees chairman Tony Kleanthous told the club's official website.