A driver was killed when a van crashed into lorries that had been forced to stop on a motorway near Calais by a makeshift barrier set up by migrants.
The van, registered in Poland, burst into flames. The driver's identity is not yet known.
Nine Eritreans were found in one of the lorries and taken into police custody.
In 2016, the so-called Jungle migrant camp at Calais was closed, but hundreds of people have returned to the area in the hope of reaching the UK.
Roadblocks, often built from tyres or rocks, were regularly placed on the A16 motorway leading to the port of Calais before the camp was dismantled in October. Migrants aimed to slow lorries down as they approached the port in the hope of climbing on board.
An Eritrean man was killed in an accident involving a British motorist in October. But no further incidents had been reported on the A16 until late last month.
The crash in the early hours of Tuesday was described as the first fatality involving a driver.
Two lorries were forced to stop when tree trunks were placed in the road near Guemps, 12km (8 miles) east of Calais, at around 03:45 local time (01:45 GMT), local media said.
The van was unable to brake in time and ran into the back of them. The driver died at the scene.
Police said the nine Eritreans were being questioned on suspicion of manslaughter.
Several hundred migrants are living in the Calais area in poor conditions. Some 7,000 had lived at the Jungle camp before it was dismantled.