This is not true.
The legal act that regulates it[0] says (only relevant parts)
""" Article 1: This act regulates
1) recording, collecting, developing, maintaining, making available and publishing documents of the state security authorities, obtained and collected from July 22, 1944 to July 31, 1990, as well as Third Reich and USSR security authorities, regarding:
a) crimes committed against persons of Polish nationality or Polish citizens of other nationalities in the period from November 8, 1917 to July 31, 1990: - Nazi crimes, - communist crimes, - crimes of Ukrainian nationalists and members of Ukrainian formations collaborating with the German Third Reich, - other crimes constituting crimes against peace, humanity or war crimes,
[...]
Article 55: Whoever publicly and contrary to facts denies the crimes referred to in Article 1, point 1, shall be subject to a fine or imprisonment for up to 3 years. The sentence shall be made public. """
(art and research is exempt from this law)
So it is illegal to deny Holocaust or to attribute the responsibility for it to Poland or the Polish nation or to say that the death camps linked to Holocaust were Polish or operated by Poland.
It is legal to suggest or just simply say (as it is documented by the Institute of National Remembrance - a Polish state research institute) that there were individual Polish citizens that collaborated with Nazis and took part in committing Nazi crimes.
[0] https://sip.lex.pl/akty-prawne/dzu-dziennik-ustaw/instytut-p...
The problem is with this bit:
"Article 55: Whoever publicly and contrary to facts denies the crimes referred to in Article 1, point 1, shall be subject to a fine or imprisonment for up to 3 years. The sentence shall be made public"
It just says "contrary to fact". And as many experts have already pointed out, it allows the prosecutors to define what the "fact" is. Not historians. Today you can freely say that Poles have killed 400 Jews in Jedwabne and yeah maybe you won't get arrested. Tomorrow? With the way the current political system is going? I wouldn't be so sure.
>>no one restricts them in any way.
Yes, because scientific research is explicitly excluded from that law.
https://www.bbc.co.uk/news/world-europe-44627129
When Poland made it a criminal offence this year to accuse it of complicity in Nazi war crimes, there was an outcry in Europe, Israel and the US.
Anyone found guilty could face up to three years in jail.
Five months later, the right-wing prime minister has moved to change the law to decriminalise the offence, describing it as a "correction".
An amendment to the Holocaust law was quickly backed by the lower house of parliament and now moves to the Senate.
The law had been intended to "defend the good name of Poland" but from now on it would be a civil, not a criminal offence, the head of prime minister's office, Michal Dworczyk, told public radio.