When police raided Farid's home near Paris they found 305 grammes of cannabis resin and 60,700 euros cash in a cigar box, Le Monde newspaper reports.
The drugs and the cash were seized and officials later confiscated a car, a scooter and the balance in his bank accounts.
But that was not enough for France's tax authorities, who, since 2009, have had the right to tax income from "certain criminal undertakings" estimated on the basis of the subject's lifestyle.
Farid claims to have believed the bill was a mistake at first.
"To me dealing was a way to get by, it wasn't a real job, it wasn't liablme to tax," he told Le Monde.
After leaving prison he found a minimum-wage job as a waiter and the tax authorities allowed him to pay part of the debt in 50-euros-a-month instalments but not all, leading to fines for not paying and an accumulated debt of 43,131 euros.
Farid's social worker, Nathalie Vallet-Papathéodorou has appealed to officials to drop the demand on the grounds that it obstructs his reintegration into society and "implies that drug-pushing is a job like any other".