We have been offered someone's apartment in the Montparnasse area in July, free of charge so we can't pass up this offer. We have not been to Paris before. Could you please give us some tips on using the transport network as well as the best way to travel from Montparnasse to the usual sights e.g. Louvre, Eiffel, Ille de la Cite etc. Any travelling tips for a non French speaking first timer?