As of today, 1 July, Croatia is a member of the European Union. Though it is not yet a member of the Eurozone, and maintains its national currency (the Kuna) at this time, it is anticipated and expected that it will transition to the Euro, on schedule, in two or three years.
The issue is that good money launderers have been known to move assets into, and make investments in, new member countries, before they join the Eurozone, knowing that, in the hustle and bustle of exchanging currency, when it does occur in the near future, is a valuable opportunity. It is impossible to ask every Croatian who has kept cash at home to document the Source of Funds of their savings; lack of staff, other fiscal responsibilities, and the chaos of the event, all add up to a gap that can be exploited.
Therefore, should you notice bank clients, who heretofore had no trade or other business in Croatia, moving funds there, or making substantial investments, you may wish to take a closer look at your customer.