From city to city, the train route are well specified. One of the well-known train company in Europe that I traveled with is TGV http://www.tgv-europe.com/en/.
I booked my train ticket online. The earlier you book online, the fare is cheaper. TGV allows you to collect their ticket in various modes. One of my Malaysian friend collect the TGV ticket that she book online from one of the office in Puchong. To collect from Malaysia, make sure that you allow enough time for the ticket to be sent from Europe to Malaysia, 3 days to a week.
For me, I booked online when I was Malaysia and collected the ticket in Europe via machine. Very convenient. If you want to collect in Europe, ensure that you choose country as France or Luxembourg and use the same credit card that you used to purchase the ticket online when you want to retrieve the ticket from machine at France or Luxembourg station.
In Paris, my tour-guide was the metro (underground train) map. It is tremendously useful. Thanks to the metro Paris for the map (it is free!)
http://parisbytrain.com/tag/paris-metro/.
One night stay in Paris can be easy too. You can have luxury hotel under romantic light of Eiffel Tower or budget stay.
I chose budget stay. I stayed at Aloha Hostel (EUR25 with breakfast, yes! the cheapest that I can find online) in female dorm, 5 min walk from Volontaires (means 'It's my pleasure') metro station. The hostel is small but cosy and good enough for a night sleep, shower, and breakfast. You can rent bedsheet and get Internet access. Recommended for budget stay.
http://www.aloha.fr/eng-acces.php
Hop onto metro at Volontaires station (line 12, green) and stop at Assemblee Nationale, you walk along the river for 15 min, then you can reach the Eiffel Tower.
If you want to get more information and get help when you travel in Western Europe, learn up some French word. Bonjour, Merci, désolé, Un, Deux, Trois, Parlez-vous anglais? s'il vous plait, and Oui...(not exclusive list). You will definitely find them useful in understanding announcement in train stations.
You can get some start up lesson for free at http://www.bonjour.com/index.php?lesson=1
Au revoir !
