Christian Prudhomme, director of the Tour and central figure at the start of the stages, was not at the start of the 10th stage on the island of Oléron on Tuesday, towards the island of Ré.
The Tour director, tested for the 4th time on Monday in La Rochelle, tested positive for Covid-19.
He must be set back from the race for a week.
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Tour de France: no positive case for Covid-19