Benzema is accused of participating in a plot to extort money from Valbuena via the reported existence of a sex tape involving the Lyon midfielder and his partner.
The striker and co-defendant Karim Zenati contested the legality of the investigation into the situation, claiming that some of their conversations had been illegally listened in to.
Benzema's lawyer Patrice Spinosi accused an undercover policeman of provoking the commission of the offence and, while the application for the process to be annulled was initially rejected in December, France's supreme court of appeal has today ordered a re-examination of the charge.
"It is certainly a big victory. In practice, this must mean that the evidence against Karim Benzema is set aside," Mr Spinosi told France Info.
The decision does not clear Benzema of any wrongdoing, but does recognise that aspects of the police investigation had broken rules.