French river police practice on the Seine ahead of Olympics opening ceremony

French river police trained on the Parisian river on Tuesday in preparation for the Olympics opening ceremony later in the month.

About 10,000 athletes will be parading on more than 90 boats on the Seine for 6 kilometres.

The open-air ceremony will be held during sunset and is expected to last nearly four hours, transforming Paris and its iconic landmarks into a giant stage.

A large police operation is planned for the event.

"We will have several boats involved with other police units from outside the Prefecture of Police," said Sophie Malherbe, the Head of Department of the Paris River police.

"This will involve securing the fleet during the parade, as well as securing the Seine river bank," she added.

Paris' police chief Laurent Nunez has announced plans to deploy around 30,000 police officers each day, including armed police, with a peak of 45,000 for the opening ceremony on the river Seine.

The police will be supported by the military, with about 18,000 members of the army involved during the competition.

About 220,000 invited and security-screened spectators are expected to fill the upper tiers of the river’s banks, and another 100,000 paying spectators will watch from the lower riverside and around the Trocadéro plaza.