One of the things I was most concerned about with being a Vegan at Disneyland Paris was the counter/quick service options. With table service it's easy enough to get something replaced or substituted, but most counter service meals are pre-made/made in bulk so it's harder to swap and change things. Luckily, I did manage to find some options that were meat, dairy and egg free. This, combined with some sit down meals, kept me well fed during my trip, although i would recommend taking some snacks for the hotel room/on the go munching.
Breakfast at Sequoia Lodge
The continental breakfast at Disney hotels, while very pastry and cold meat/cheese based, do offer quite a few vegan options. I did ask a cast member if any of the products I had contained any dairy/eggs, just incase, so as far as I am aware these items from the breakfast buffet are vegan. I pretty much got the same things everyday which included Frosties (frosties in europe are vegan friendly unlike their US counterparts), toast with jam and breadrolls dipped in chopped tomatoes that I used the microwave to heat up. I was also over the moon that soya milk is available so took advantage of stuffing myself full of cereal. There is also whole fruit and a fruit cocktail available, but the latter I wasn't a fan of as it tasted really bitter.
Earl of Sandwich

Earl of Sandwich has always been one of my absolute favorite places to eat at Disney, usually opting for the Caprese (€6.95). I had heard that they can substitute items in their sandwiches so off we trotted, keeping my fingers crossed that my obsession with EOS wouldn't come to a devastating end. When reaching the order point I asked the lady if I could substitute the mozzarella cheese in the caprese for avocado, to which she replied "are you a vegan?" Wait what... someone who knows what a Vegan is? Oh praise Walt! She then proceeded to ask the manager if i could get the avocado at no extra cost as i wasn't having cheese (usually its extra), to which they agreed. The lady then told me that she was becoming a Vegan herself and that the rest of the sandwich is suitable. Needless to say by this point I was beaming. We power walked back to the hotel and I devoured my sandwich, which I do have to say, was absolutely amazing. I need another one in my life asap!
Bella Notte
Bella Norte is probably one of the only counter service locations in Disneyland Paris that has a Vegan meal already on the menu, that isn't salad or chips. The Rigatoni Napolitana (€8.99) is pretty much a pasta with tomato sauce, but its delicious! Simply yet satisfying. I had it twice during the trip, once as a meal (€11.99) with the side salad (the dressing for that is also vegan, having a white bean base for the light colouring). There is also a vegetarian salad that's vegan which my friend had and said its very good.
Market House Deli
Before I went to Disneyland Paris I read on a blog that the Bagnat aux légumes grillés (€6) served at Market House Deli had recently become Vegan friendly. It used to be made with pesto which contained dairy, but has since been replaced by an aubergine paste. The sandwich contains a medley of roasted vegetables and rocket, which combined with the paste makes a tasty lunch option. I'm not a big fan of wholemeal breads and seeds, but the filling sure made up for that. I would double check that it isn't made with pesto in future, as recipes can change, i asked the lady on the till and she confirmed there was no pesto in it.
Snacks
I didn't have many snacks during this trip, mostly just devouring bucket loads of tea to counteract the cold weather. One evening I did treat myself to a bucket of popcorn, which the vendor said was made with popcorn kernels, sugar and vegetable oil. The popcorn in Walt Disney World is made this way and is suitable for vegans (I used to work on the popcorn stands in Magic Kingdom), so I'm pretty confident that Disneyland Paris follows suit. I also had a soya milk hot chocolate from Starbucks on the walk back to the hotel once or twice. There are also chips/fries available from most counter service locations which are great for a light lunch or for when you are feeling just a bit peckish, just ask to make sure they aren't cooked with the meat.
I do suggest you make your own enquiries when visiting Disneyland Paris, as recipes can change and language barriers can mean the wrong information is given. There isn't a massive selection of Vegan food as compared with the American parks, but it's a start and I hope in the future they will provide a lot more options for those with specific dietary requirements. Just know that you're not going to starve and that i would recommend doing your research before a visit.
xox