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…