I did my internship this year in a travel agency that PI found for me. I wanna thank to Premium Internship for their support before and during my Erasmus mobility.
It was difficult with the accommodation as the city is very busy in spring time but we manage it in the end.
I recommend this company and Barcelona city especially in the spring-summer time. Make sure you inform there asap about your departure date/time so they can have enough time for finding a room. All barcelona is safe but try to avoid Besos and Raval district for accommodation.
Hope to get my second Erasmus programe and come again to Barcelona. Very nice place to be.
Don't forget to join their meetup trips: GoToExplore as we will meet many international students and the locations are pretty nice.