In Croatia, Petaci families are Croats (from Zagreb ).
Prevalence
Only a few people with faimily name Petaci live in Croatia today, in one household only. There were 20 of them in the middle of the past century, and their number halved. They are located in one Croatian city only, in Zagreb (<10).
In the sources analysed in the project Acta Croatica so far, the name is mentioned over ten times, the first time 1902 in source Hartmann's General List of Apartments in Zagreb.