This rehearsal, between the Pont d'Austerlitz and the Pont d'Iena, was originally scheduled for the beginning of April, but was postponed twice due to the excessive flow of the river caused by the many storms that marked the spring in the Île-de-France region. A first test also took place on 17 July 2023, this time with around forty boats.

The boats should take 45 minutes to complete their journey. The 55 boats set off from the Pont d'Austerlitz at around 6.30am on Monday morning, with navigation on the Seine suspended at 4.30am for this test.

"The first trace of the first practice, we were clearly a few minutes behind schedule," recalled Thierry Reboul, Director of Ceremonies for the Organising Committee, during a press conference. "We have learnt from that, we are continuing to train and today we are very happy with the timing and the way it has been adhered to. We are practically on time for all the boats, for each boat to the second, we are very happy," he assured. 

"The focus of our training is on timing, on the ability of the boats to navigate together, of course, but above all on keeping to a schedule so that we can present our delegations at the right place, almost to the second, when we need to present them," explained Thierry Reboul, Director of Ceremonies for the Organising Committee. A similar test is planned for 24 June, but this time with all 89 boats.

One of the main concerns is the flow of the Seine, which increases with rainfall and makes navigation more difficult. "The flow of the river has reduced quite significantly and quite quickly. We are still at a significant flow, but we are getting much closer to the conditions we usually see in July," explained Thierry Reboul.