Low spread forex brokers and other financial services companies in Poland are regulated by the Polish Financial Supervision Authority, known locally as Komisje Nadzoru Finansowego (KNF). Although Poland is not home to that many forex brokers, there is a pretty large community of forex & CFD traders in Poland, and many of them obviously appreciates the chance of trading with a local low spread broker.
As an EU member state, any forex broker regulated in Poland is also allowed to market its services to traders in other EU countries, and vice versa. This makes it easy for Polish forex traders to compare brokers across borders in Europe in search of the lowest spreads that are available.