The French supreme court has annulled the 2014 appointment of a French Polynesian minister, Tea Frogier.
It upheld a complaint by a citizen, Yves Conroy, who pointed out that she had been chosen as labour minister despite not being eligible.
By law, there is a stand-down period for a public servant before being allowed to be a minister.
However, the court said the decisions she made as minister still stood.
The government has reportedly shrugged off the ruling as a non-event and is reportedly poised to reappoint her.