You should budget approximately the following amounts:
– Transportation: the cheapest way is to buy the Navigo travelcard for about 65,00€ per month, which allows you to travel in Paris by bus and subway.
– Living expenses: 450-500€ per month
– Housing:
1) A room in someone’s home: 400 – 600€ per month
2) Studio (furnished): 600-900€ per month
3) 2 room apartment (furnished): 900-1500€ per month