Been to both. Paris first, see the tourist sites and leave. Parisians are rude and do not tolerate tourists well that do not speak Parisian French. Spend time in Barcelona and at the beach. Spain may not be the best place economically right now but the people are welcoming. The history is incredible and the arts are well represented with the Picasso Museum among others and Gaudi's architectural wonders are spread over the city. If you get the chance, take a side tour to Toledo. It is a medieval walled city that is still complete and was once known worldwide for its superior steel swords. Have fun and enjoy your trip.