Antony de Malmanche was arrested in December at Bali's airport with 1.7 kilograms (3.9 pounds) of methamphetamine in his baggage.
The Denpasar District Court ruled Tuesday that 53-year-old Malmanche was guilty of violating the country's anti-drug laws.
The panel of judges also fined Malmanche $300,000 or an additional three months in prison.
Indonesia has extremely strict drug laws and convicted smugglers are often executed. More than 140 people are on death row, mostly for drug crimes.