"Casey Junior - Le Petit Train du Cirque" and "Le Pays des Contes de Fées" were added to the resort in March 1994 as part of an expansion plan intended to add a maximum of capacity to the park. Since no space had been saved for these two rides in the original plans, they were built outside the railroad tracks surrounding the park.
Imagineers took their inspiration from similar attractions in Disneyland California, the Casey Junior Circus Train and Storybook Land Canal Boats. In Walt Disney's first Fantasyland, two trains and a fleet of small boats (all self-propelled with a Cast Member on board) carry visitors past miniature fairy tale dioramas and landscapes.
Concept art © Disney
In Paris, Casey Junior became a powered coaster (unlike traditional roller coasters it doesn't run on gravity but on electricity) while the boats of Storybook Land were no longer propelled by individual engines but pulled by a cable in an endless chain. The operator's live narration on the boats was replaced by appropriate music in each scene. In most cases, the cue was taken from the respective Disney film. For the Wizard of Oz scene, they used the Oz segment heard in the Main Street Electrical Parade, a synth rearrangement of music from Disney's Return to Oz.
The music of Casey Junior uses an early version of the roller coaster on-board sound system used in rides like Space Mountain or Rock'n'Roller Coaster. Separate sensors trigger the ride's main audio and the safety spiel.
The giant storybook on the Storybook Cruise load platform shows the castle from "Mickey and the Beanstalk." If you zoom in really close (like, really, really close), you'll see two pairs of initials on the castle's flags… probably those of the artists who painted the full-scale illustration.
A reference to the original Imagineers who created the attraction can be found in the Night on Bald Mountain scene: extremely sharp eyes can read their names on the tiny graveyard's tombstones.
Few changes were made to these attractions over the years… For its first few years, Le Pays des Contes de Fées was sponsored by Mattel. Small characters were added to the vignettes a short time after opening. Spiels were replaced. Most notably, the miniature tower of Rapunzel was replaced by a movie-accurate version when "Tangled" was released in 2010. Here's a good look at the original tower:
The Storybook Cruise boats all sport the French names of female Disney characters. In alphabetic order, they're Alice, Ariel, Aurore, Belle, Belle Marianne (Maid Marian), Blanche Neige (Snow White), Bianca, Cendrillon (Cinderella), Clochette (Tinker Bell), Duchesse, Féline (Faline), Flore (Flora), Jasmine, Lili la Tigresse (Tiger Lilly), Mary Poppins, Pâquerette (Merryweather), Pocahontas, and Wendy.
As a bonus, here's my fan-made poster for Le Pays des Contes de Fées, closely based on the original Storybook Land poster from Disneyland.