French police discovered a massive haul of cannabis resin in a van on the A40 autoroute, close to the Geneva border.
Police had targeted the van earlier as they felt the driver was acting suspiciously.
When it had stopped in a rest area police arrested the driver and searched the van. They found half a tonne of cannabis resin packed into 15 suitcases.
The 30-year-old man is now in pre-trial custody. He told police he had been told to drop off the drugs in Annemasse.