How much cash should I bring on a three week study abroad to France?

take some sufficient cash along say Rs5000 and some travellers cheque and credit cards along with u...

France is very expensive. I went there 4 years ago back packing. I suggest you go to the grocery store whenever possible instead of eating at restaurants. Also, make sure if you get a coffee or drink, stand at the bar, they charge extra when you sit at a table. If you get a chance, buy a Lonely planet book or some kind of guide book, they are great for making sure you find the best deals at places to stay, restaurants, bars & attractions. Good luck & have fun!

All that you have and borrow some to get home on from your friends.

I can't say a for-sure dollar amount, but I'd say a lot! You'll want to sample the culture of France as much as possible which may mean eating out quite a few times, shopping around, and sites (museums and other attractions that may have an admittance fee.) I suggest, take more than you need so that way you won't run. Have fun!

Very little, buy a prepaid credit card and some travlers checks. Don't get ripped off!!

depends how much you drink, if you like to party probably 5-600 American