The Cayenne appeals court on Monday threw out a lower court's sentence of nine months in prison, a 50,000-euro fine and a five-year ban on holding public office on Leclère on Monday.
The sentence was stiffer than the one proposed by prosecutors but that was not the problem.
The court ruled that the organisation that brought the case - a party called Walwari that was cofounded by Taubira herself in 1993 - was not qualified to do so.
Its statutes did not define its aims as to "defend the memory of slaves and their descendants" and "fight racism" five years before the alleged offence was committed in 2013, as required by law, the court said.
Leclère's lawyers raised various other arguments against the sentence but the appeals court did not consider them.
The original judgement also fined the Front National 30,000 euros.
Leclère's lawyer, Jérôme Triomphe, said that the "discredit brought on the law by the scandalous sentence" had been lifted and that he was considering taking legal action against the magistrates involved.
Walwari insisted that the ruling was based on a technicality.
Triomphe will have more work to do soon, however.
Paris prosecutors had planned to take Leclère to court in September 2014 but that was postponed because of procedural problems raised by the Cayenne sentence.
That case is to be heard next September.