there are five RER lines in Paris (ABCDE) - They are operated by the public transportation service RATP - (interactive maps in link)
It's not the Métro (RATP), but the suburban railway (RER, Line A).See this link:http://parisbytrain.com/rer-train-paris-to-euro-disney/
Auber - Paris RER - was created in 1971.
Champigny - Paris RER - was created in 1859.
The RER train line from Paris is the RER "A" branch, towards "Marne La Vallée - Chessy - Parcs Disneyland". You can board in Paris "Chatelet les Halles" or "Gare de Lyon". The arrival station is in walking distance from the entrance of the parks (or you may use the shuttles as well)
ALL RER stations in Paris are underground, and some in the suburb too. out of Paris, most RER stations are ground level or elevated.
== == Disneyland Paris is served by the RER Marne La Vallee Chessy station. One needs to use the RER-Line A. The nearest RER station to the Louvre where one can board RER-Line A is the Châtelet - Les Halles (Paris RER station). The Louvre is about 1.5km (one mile) to the Châtelet - Les Halles (RER station). One can walk. If one wants to use the metro, then go to the Palais Royal/Louvre metro station; take either Line 1 or Line 7; go to/get off at the Chatelet metro station, and board the RER-Line A to Marne La Vallee Chessy.
Joinville-le-Pont - Paris RER - was created in 1859.
Épinay-sur-Seine - Paris RER - was created in 1908.
You take the RER A
It is midway between Saint-Michel-Notre-Dame and Luxembourg on Line B.
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You can find a detailed map of the Paris RER on the Paris By Train. The map is pretty small, so you are going to have to click and zoom in on it to see any details.