Phew... make it a long day! IMHO, Disneyland Parc first - SM:M2 usually has the biggest queue. Then over to the otherside and do BTM. Get a fast pass for Indy or PotC and do the other. Then Phantom Manor (before the queues build.) Its a Small World is great too, not usually to much of a queue (loads fast)
Then the studios; RocknRollercoaster, Armageddon (queue dependant), save Moteurs Action! for WDW since you don`t have much time, and if you time it right don`t miss Cinemagique. If you like dark rides, the 3 in Fantasyland are excellent ones but do get very popular so you may take this into consideration (PeterPansFlight has fast fass though)
To sum it up; Phantom Manor, PotC, BTM, IASW and SM are Disney at its best. If you only do one park I`d reluctantly miss the studios out and do as much of Disneyland Parc as possible. Honey I shrunk... and Star Tours are identical to WDW. Make sure you take some time to look in the stores (the theming and decor is amazing) and try your best to see a showing of Legend of the Lion King - an absolute stunner of a stage show. Tickets are free, first come first served, around 11am in a queue next to Discoveryland Rail Stations entrance - double check that time though, and make sure you get an English show.
Finally, beg borrow or yell to stay for Fantillusion... I won`t spoil it. Just don`t miss it. Try to watch it from the hub with a view of the castle in the background (opposite the drawbridge to the side of the disabled area is superb but the bare minimum `bum on kerb` time is 45 minutes before parade time. Wishes is straight after.
Enjoy!!