Go to Paris in summer and you will see young men selling bottled water around Metro stations and outside Galeries Lafayette. They try to keep the bottles cool in plastic buckets. They charge just one euro so they aren't going to get rich, though they are probably going to get moved on.
Strolling the other day on the Champs Elysée, it struck me that very few tourists were carrying bottles of water. That's odd, I thought. In London, everyone - certainly every young tourist - walks round with a bottle of water in hand.
Then I began to figure it out. Big streets in Paris have plenty of big kiosks selling newspapers. The kiosks have signs reading "Presse" and "Journaux", they have always been there and they do indeed sell a wide range of publications. They don't sell bottled water. Likewise, there are quite a few tobacconists attached to cafes and bars - but the "Tabacs" sell nicotine (and that other drug, lottery tickets), not bottled water. To get bottled water in Paris, you will have to find a (North African) convenience food store in a side street and in the more expensive districts there aren't many of them.
Hence the shortage of bottled water in Paris. By contrast, in London bottled water is sold from all kinds of storefront.
Neither city can hope to emulate Zurich, where water from the mountains pours out non-stop from city drinking fountains. If a restuarant is nearby, you may even see waiters going to the fountain to fill their water jugs.
I am not going to Google this to find the answer, but I wonder if the Paris Presse kiosks and the Tabacs are simply conservative or, alternatively, don't actually have permission in their licences to sell water. Retail activity is minutely regulated in France and you can see how restrictions on water selling would advantage the cafes, since some people will sit down for a drink when none is available to walk around with. But I leave it to Evian and Vittel to find out. Either way, they should launch a campaign to make their products as accessible in Paris as they are in London.