Traveling to Paris with Dialysis

First issue, you don't say where you are from, so I don't know what the electrical supply is where you are. But, can your dialysis equipment run on 220V 50 Hz AC? If not, you will need electrical converter (exactly what depends on your equipment.
French customs should not be an issue. If it is clearly medical, and you are bringing it with you, no problem.

Several people have posted about travel with dialysis -- to find the posts, go to the "search" box at the upper left of the page and type in "dialysis"

I'm not sure what you mean by "dialysis supplies". What kind of dialysis are you doing? Hemodialysis? You're not doing that yourself, are you? There are hemodialysis clinics in Paris. I know because I visited some there when I worked for a dialysis equipment company some years ago. Our equipment back then accepted any voltage, probably from 100V (Japan) to 250V (Australia).