> and every summer, young people, possibly a little drunk, jump into the water as a dare from bridges near Notre-Dame

After ending high school exams in 1993, we jumped into the Seine from Pont de Neuilly. I suppose this sort of antics have been going on since times immemorial and without counting bacteria beforehand... But I'm glad the river has cleaned up !

My first impression upon hitting the water: 1 - it is actually water (I expected mud !), 2 - wow, there is actually current and the shore goes by rather fast... No problems of any sort.

Anyway, it is fun - do it, and have a spotter to check for ships !