My initial thought is that Paris and capital cities outside of North America do not usually have timeshares in the heart of them, and many that do are not up to the standards we have enjoyed elsewhere (there are some exceptions as Marriott has properties in Thailand and Spain). Other than the Marriott that you've been to, I have only seen a couple ever listed for Paris and the photos did not make me want to book. I would only consider a purchase in Paris if I had rented from an owner first, loved it, and then run the numbers to see if it makes sense to own. Maintenance fees last forever and increase each year, and not all timeshare systems are created equally. It's great that you are here to do your research though.
I am off to Paris in a few weeks and there are so many great hotels and areas, I personally enjoy trying something new each trip without having to plan so far in advance. I don't know if you saw the worksheet of questions to help you decide if timesharing is a good fit for how you travel and your goals, but it is a worthwhile exercise before taking the plunge into any timeshare purchase.
Best of luck in your search. I look forward to seeing if there are some gems out there we have not seen. I know there are some fractionals out there (starting at about a 4 week purchase), but they are very expensive IMO. I'm not sure how many weeks you were thinking of purchasing or your budget, but you may want to take a look and see what the latest price is.