Distilled water for CPAP

You can find it in grocery stores or places that sell cleaning supplies - a 1-liter bottle may have a picture of a steam iron on it, since that is one of its specific uses. It will cost much less than buying intact a pharmacy.

Try looking for eau distillée (two e, with the accent on the first one).
I would try a "pharmacie" rather than a supermarket, and try to explain what you want it for.
If it helps, CPAP = Ventilation en pression positive continue

I hate to tell you, but most people just use tap water in their CPAP. One of the bottled waters would also work vs. chasing all over town looking for specifically distilled water.

Look for "eau déminéralisée" in the cleaning section of any supermarket. It's usually sold in 2 liter or larger plastic jugs and is normally on the bottom shelf. It's very cheap.
It's not advisable to use Parisian tap water in a CPAP machine, due to the variability of the mineral content in any given building.

As chexbres said "eau démineralisée". If a pharmacy even stocks it, it will be 4 euros, but if you go to any large supermarket, such as Monoprix or Franprix, it will be 1 euro. As stated, it's on the bottom shelf in cleaning supply section because it's bought for ironing. If you don't spot it, ask an employee. Paris water is full of calcium, so it's best to get a bottle of water.

Yes, I just use tap water and then clean the water tank out when I get home.

Sandy: As chexbres said, ask for "eau démineralisée". And, get it in a supermarket, not a pharmacy. When I first traveled to Paris with a CPAP, I had initially gone to a pharmacy and asked for "eau distillee". The pharmacist had a strange look on her face so I explained why I needed it. She told me I needed "eau démineralisée", which was cheaper, and told me to go across the street to the supermarket and get it there. Ever since, when I get to Paris, I just get it at the supermarket along with the other basics (adult beverages and snacks)! While traveling by car around Europe, you can also get it at service stations--they use distilled water to add to car batteries. Safe travels and enjoy Paris!

~Darrel

That's what distilled water is - demineralized. Keeps crusty calcium from building up on your devices.

Thank you for all you help unlike the 8 pharmacies I visited. I was finally directed to a Monoprix which we had a terrible time finding in the wind and light rain. They kept telling me it was upstairs and I could see all the cleaning products but the lady said it was downstairs, after they had told me it was upstairs. I found the man again and he used his phone and the two of them argued and argued. Finally he went upstairs and brought down a liter of water that had been demineralized. I could easily find water sans minerals but The pharmacist said that was not the same thing. Thank you again for all your help as we have what we need now. So much for a French English online dictionary. It wasn't until I started talking about water for an iron that they finally began to understand.

Many Monoprix stores have food items located upstairs or downstairs, and everything else - including cleaning items - will be located in a different area. Nobody knows why this is, but it can be very annoying - especially since the large shopping carts are where the food is!