Location of Gare de Lyon. In Paris, capitial of France, see http://fr.wikipedia.org/wiki/Gare_de_Lyon
You can walk - the two stations are at opposite sides of the river, but not very far apart. More practically (if you have luggage) you can go by bus - number 61 does the trip in 5 minutes. As you...
22.33 kilometres (13.87 miles)
On the RER (express underground) Line D.
you take the RER from Auber