Disneyland Resort Paris, originally known as Euro Disney, is a theme park run by the Disneyland company in Marne-la-Vallée near Paris. Construction began in 1988 and the theme park complex officially opened on April 12, 1992, but attendances were low and there were protests by those who thought a Disney park in France would harm French culture.
In October 1994, the former Euro Disney changed its name to Disneyland Paris, and now to Disneyland Resort Paris. By 1995, Disneyland Paris started to attract more visitors and what began as a near failure for the Walt Disney Company has become more successful.
Disneyland Resort Paris is between the original Disneyland and the larger Walt Disney World in size. Disneyland Paris has five major sections: its version of the Disneyland theme park (Magic Kingdom, essentially); the Walt Disney Studios Park, a theme park similar to Walt Disney World's Disney/MGM Studios; its version of the Disney Village; the Disney Hotels area; and Golf Disneyland.
The park is easily reached by car. When coming near Paris, large billboards with Mickey Mouse on them will point the way. The park also has its own trainstation where the Thalys (formerly the TGV) stops and its own metrostation, so when visiting Paris you can hop on the metro and stop right in the park. Be aware though that the park lies outside of the central Paris metrozones and that you need to buy a (slightly) more expensive ticket to avoid a fine (and to be able to go trough the exit tourniquets at the station).