This is the stage of the holiday destinations and the first of three Breton stages. It starts from La Baule, known for its 9km beach.
It was the venue of the Grand Départ 30 years ago for the only Tour de France that had a preface rather than a prologue. It didn't count for the overall classification, but it was a 3.8km team time trial with the last kilometre to be covered solo by one rider per team.
Stage 4 won't be the hardest of the 105th Tour de France for sure. Going through Pontchâteau, which hosted the cyclo-cross world championship on several occasions, the course brings the riders back to the Atlantique in the beautiful gulf of the Morbihan [the name of that province means the small sea, literally translated from Breton language] and precisely to the city of Sarzeau, whose mayor is the president of the Union Cycliste Internationale David Lappartient.
The 4km straight line - the longest in French cycling since the avenue de Grammont can't be fully used for Paris-Tours anymore - is suitable for a splendid sprint finish.