Paris - Police believe that the "excessive speed" of a tourist riverboat led to the sinking of a private launch on the Seine river in the heart of Paris in which two people died, French media reported on Monday.

The riverboat's captain and co-captain were taken into custody late Saturday, shortly after their boat collided with the cruiser under a bridge near the Notre Dame Cathedral.

They could face charges of manslaughter.

The daily Le Figaro on Monday quoted an investigator as saying that the captain admitted that he had "navigated at a higher speed than what is authorized."

On the stretch of river where the accident took place, boats must travel at a speed between 6 and 12 kilometres per hour.

The private yacht was carrying 12 people when it sank.

Rescuers were able to pluck 10 of them out of the river, but a 45- year-old man and a 6-year-old boy were trapped in the boat and died early Sunday in hospital.

The incident was the first boat accident in Paris since August 1997, when a cabin cruiser rammed a bridge support, injuring 27 tourists. (dpa)