Well it will depend what exactly are you looking to do in France but for an approximate calculation
Airplane from skyscan you can find flight tickets from 5500 to 6000 return
Hotel search for 3 persons might be 100 euros each person or more
And about 500 each for fun
Also there are stuff you can use to help with the expenses like buy transportation ticket for a week let's you take the bus,train and trum