The ruling – which was largely a technicality and not based on the case itself – now gives Serge Atlaoui the chance to ask for a softening of his sentence or a pardon from President Emmanuel Macron which could see him released after a two-decade ordeal.
Atlaoui, a 61-year-old welder from Metz in northeastern France, has always denied being a drug trafficker.
The Indonesian ruling “is equivalent in French law to the production… of drugs in an organised gang, which is punishable by 30 years in prison,” the court in Pontoise, north of Paris, said at the hearing.
The death penalty was abolished in France in 1981.
Prosecutors had earlier said that the death sentence should be turned into a life term in France.
The French judiciary has emphasised it is not competent to judge the case itself after the rulings by the Indonesian authorities and can only convert the sentence into the equivalent French term.
Atlaoui’s lawyer Richard Sedillot said he could now lodge requests for both a softening of the sentence and a French presidential pardon.
“His ordeal can be ended, it will take a few more weeks,” he said.