Welcome!
Let's start with the official page:
https://www.disneylandparis.com/en-gb/guest-services/guests-with-mobility-disabilities/
Take a good read about the section on bringing a doctor's letter as proof.
Restaurants are all accessible for wheelchairs, and for the rides, it can differ per ride where you go.
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And borrowed from
@olafLover
Handicaps:
General:
In DLP there are two type of priority cards, the Easy Access Card (orange) for temporary disabilities and the Priority Card (green) for permanent disabilities. To get a priority card you have to show proof of your disability at guest services (or bureau passport annual if you have an annual pass). Proof of disability can be an European Parking permit for disabled people or an European disability card. A letter from physician is also sufficient. The letter must be written in French or English, be printed on official paper or contain a stamp of the physician and can be no more than 3 months old. Whether you get an orange or a green card is completely at the discretion of the CM, there are reports of people using the same letter and on trip getting a green card, while the next trip they get orange. If you use a letter, make sure it’s noted why the disability prevents you from waiting in line and if it’s permanent.
Without proof of disability, you won’t get a priority pass! Make sure your entire party is present when you apply for the card, the amount of people allowed to accompany you on the ride may depend on it. They will mark the tickets of the entire party. A maximum of 4 people are allowed to accompany you on rides and one person at the parade and shows.
More information about the specific rides can be found here:
https://brochure.disneylandparis.com/HCP/UK/catalogue/index.html
Easy Access Card (orange):
The easy access card, for temporary disabilities work kind of like a fast pass, but for all rides. Show your card to the CM at the entrance or the disabled entrance of the ride. Here you’ll get a return time noted on your card. The return time will be the current wait time, minus 10 minutes. At your return time, you can enter the ride via the disabled entrance. You can only have one active ride on your card at any given time.
Priority Card (green):
With the priority card you’ll be given direct access to the ride. Show your card to the CM at the entrance or the disabled entrance of the ride and you’ll be allowed on the ride.
Rentals:
You can rent a wheelchair in both parks. They are on a first come, first served basis, but you’re allowed to take them from one park to the other. They are very basic and not very comfortable. Good enough in case of an emergency, but if you can, take your own or rent elsewhere. Mobility scooters aren’t generally used in Europe and you can’t rent them on property.
Character meets:
Organized character meets with a priority card are organized in a fast pass like kind of way. Go to the handler of the character (with the entire group of people who’ll want to meet the character!) and show the card. The CM will note your name on a list and you’ll get a piece of paper with the time you can return. Because the piece will have the number of people in the party in it, it’s important everybody it there while you make the appointment. At your return time, show your paper to the CM and after one or two families it’ll be your turn to meet the character. Be advised there are a limited amount of time slots available and they do run out! If you really want to meet a character, make sure you’re there at the start of the session.
Meet Mickey and the princess pavilion have a separate entrance and their admission will be similar to rides.
In Walt Disney Studio’s they are currently using the Lineberty app for almost all meets. The priority cards are not valid at these meets. You’ll need to make a reservation in the app like everybody else.
There is nothing in place for the roaming characters. You might get lucky and encounter a CM who will honor the priority card, but most likely you won’t.