well, that depends if you're travelling by car, train or plane. I'd say anywhere from 12 hours (chunnel/car/train) to just a few by plane.
By train - overnight train 'Trenhotel' leaves Barcelona Estacion Del Norte at 9pm and arrives Paris Austerlitz station at 9am (making 4 short stops en route) By plane - depending on which airport you...
A train ride from Paris to Barcelona would take between 3-4 hours, not factoring for time spent refuelling or disembarking at other stops.
Usually about five days.
it takes about 2 hours