I strongly recommend this place. It's greatly located in Poble Sec which is full of bars and restaurants just a few steps away. It's also close to many of Barcelona's known locations (youcan get to La Rambla, Placa d'Espanya, Montjuic on foot) . Apartment itself is really nice. It's cosy but spacious and can easily accommodate 4 people.
Nicolas is a great host. He's willing to help; he welcomed us and was very nice although we came late at night. And even there was a bottle of wine waiting for us on arrival!