The 16-year old striker came through the ranks at homeland side Ciablia Vincovci, where he broke into the first-team last season, making a handful of appearances.
A number of European clubs were believed to have been tracking the highly-rated teenager, and he revealed that he snubbed apparent Premier League interest in favour of joining Fiorentina.
"I confirm I have reached an agreement with Fiorentina. Inter, Liverpool and (Manchester) City followed me too, but I've chosen Fiorentina," he told tuttomercatoweb.com.
"They have shown since the beginning to be a serious side and to be very interested in me.
Fiorentina have already bolstered their attacking options this summer with the signing of Mario Gomez from Bayern Munich, and Dabro is hoping to benefit from working with the former German Footballer of the Year.
"What striker am I like? I am like Cavani, Falcao, Van Persie and Mario Gomez. And so, although initially I'm going to play in the Fiorentina's youth, it will be a great opportunity for me to see the German bomber (Gomez) play very closely to me. I cannot wait," he said.