A two-month old infant and his mother, who had been sitting near the front of one of the vehicles, were among those killed in Pont Sonde, police officer Sem Calixte said. About 30 people had been sitting in the van.
The member of the Chamber of Deputies, who was not named by police, suffered a chest injury and was hospitalized.
"It's a terrible accident," Calixte said.
Court official Thielot Catilus said "many people were seriously injured," and at least 10 people were taken by ambulance to hospital.