What may be the cost for three weeks' budget travel in France?

I am planning to travel to france with my family (total 3 persons) for three weeks in july 2011.How much money should we arrange for the travel excluding international air fare? We prefer budget travel.|||80 to 100 Euros a night, 80 to 100 Euros food a day, minimum. You're not saying where, what you want to visit, how you want to travel, and my crystal ball is not working so you'll have to look for the rest yourself.|||well im not sure and cuz ur not going to pay me to do ur job, the only advise is if u really want to save go to hostel.com its like $20 per person per nite intead of $120 per nit plus $20 per extra person rite. soo go luck