Quick question, to get by train from Paris "Gare du Nord" do follow this route? (not sure if i worked it out?)

Question

From Gare du Nord, take the RATP/SNCF (B) to "St-Michel Notre Dame"

Change here, take the SNCF (c) line to "Champ de Mars Tour Eiffel" ?

Is it that easy?

Answer 1

It's the easiest on the paper.

But Gare du Nord is the 3rd biggest station in the world (by nb of passengers )

easy to get lost ;-)

Answer 2

A more direct route  is to just take Bus 42 from Gare du Nord.

But yes, the route you have stated works. (Its called the RER by the way, rather than the RATP/SNCF).