The
ABD air department can book your flights. The advantage of using ABD air is if ABD cancels your trip, they will also refund the cost of your flights. If you buy the flights on your own, then you must deal with cancellations and getting credit/refunds for your flights. The disadvantage is that in the past couple of ABD trips I took, the fares I could get through ABD air were significantly higher than what I would get buying directly from the airlines.
You can buy a trip directly from ABD, but you are leaving money on the table and may have to do more work than if you used a
travel agent. ABD trips are like cruises where the price includes a commission that would go to a TA. If you buy directly from ABD, ABD will not lower the price. But if you go through a TA, most will kick back some money or credits to you while also providing services. Such as staying on the phone for hours on opening day if you're trying to get the cheapest price.
Dreams Unlimited is a
travel agency that sponsors this board.
You could also consider arranging
Disneyland Paris on your own. There is a separate forum for that:
https://www.disboards.com/forums/disneyland-paris-trip-planning-community.77/
I suggest getting a taxi from Paris to the parks. While that's not cheap, it is the most convenient. From DL Paris to CDG airport, there are trains that take 10 minutes. You probably want to buy train tickets in advance.
The closest hotel (DL Paris hotel) isn't listed as an option in the ABD offering.