Retaining the title will see the Spanish club win the competition for a record fourth time, although overcoming La Viola will be a big ask.
Fiorentina overcame Tottenham, Roma and Dynamo Kiev en route to the last four and have home advantage for the second leg.
The other tie sees Rafael Benitez’s Napoli take on Dnipro Dnipropetrovsk of Ukraine for a place in the Warsaw final, which takes place on May 27.
Europa League semi-final draw:
Napoli v Dnipro??
Sevilla v Fiorentina
Ties to be played May 7 and 14.??