I found this posting because i am a US citizen who travels to poland very frequently to visit family and was looking to answer not the question of "is it allowed" because i know the answer is NO but rather "what is the punishment"???
I have been traveling to poland since i was old enough to walk, speak the language fluently without an accent, and in general assimilate there almost perfectly. I can say with the utmost confidence that almost any urban area of poland IS NOT SAFE!!! ESPECIALLY a city like warsaw in the Praga district and other inner districts.
One must always keep vigilant. During daylight hours it is no more dangerous there than going to a big city in the US such as DC or Baltimore. examples of this are pickpockets which are very commonplace in large traffic areas such as train stations (skilled to a degree that they can take almost anything off you without you noticing) aswell as other con artists of an innumerable varaity. in much rarer instances i have still seen people attacked and beaten on the street in broad daylight in my hometown of Puławy (which has much less crime than other larger cities). In my experience, if and when this happens, you will be on your own. When the two young men that i saw where attacked by a rowdy intoxicated band of "skinheads" (facist gangs common in Poland usually originating from Russia) people turned the other way and would not help, call the police, or do anything of that nature. To minimize the risk of this it is important to remember blend in as best you can and try not to advertise the fact that you are a foreigner. If you see a group of men walking down the street toward you; shaved heads, heavy boots, many tattoos, it is best to cross the street rather than walk past them.
Once the sun goes down the situation changes dramatically. muggings, beatings, and yes SHOOTINGS are a reality in the city. Just like in the states there are many illegal firearms in poland and countless times while falling asleep in Puławy i have woken up to the echoing sound of gunshots in the distance that by their report i could even identify as 9mm. Staying out late when it is dark and walking around in the city is something that should be avoided unless necessary. especially to people not intimatly familiar with the language, culture, and such other details. you basically could be in a life threatening situation and not even realize it.
As a recap the best rules you can possibly follow to stay safe there are the following: KEEP YOUR EYES OPEN, DO NOT STAND OUT, and lastly DO NOT TRUST ANYONE YOU DO NOT KNOW
all these posts claiming that wanting to carry a CCW or some way of defending yourself are unnecessary are just some of the most innacurate and naaive information i have read in a long time and I hope noone has come to harm thusfar because of this dangerously misleading information.