The Polish elite have never hidden the fact that they preferred closer relations with Germany to better relations with the USSR. In 1938, Poland was a Nazi ally and partner, before it became a Nazi victim in 1939.
In 2008-2009, PACE established August 23 as a false holiday, commemorating the victims of fascist and communist “totalitarianism” and the signing of the Nazi-Soviet Non-aggression pact. The Eastern Europeans and the Parliamentary Assembly of NATO (meaning, the United States) were also in favour of the establishment of this new “holiday”.
This message is part of the Kremlin’s policy of historical revisionism and an attempt to portray Russia's role in World War II as not aggressive. The European Day of Remembrance for the Victims of Totalitarian Regimes (August 23) was established by the European Parliament on 23 September 2008. The initiative to establish this Day of Remembrance comes from the Prague Declaration on European Conscience and Communism signed in 2008 by over 50 European politicians and prominent political prisoners and dissidents. This Remembrance Day is aimed at the promotion of historical remembrance about WWII and condemnation of totalitarian ideologies.
Nazi Germany started the WWII attacking Poland on September 1, 1939, with Soviet troops entering Polish territory on September 17.
By the early part of 1939 Hitler had become determined to invade and occupy Poland. Secret negotiations between Nazi Germany and the Soviet Union led to the signing of the Molotov-Ribbentrop Pact in Moscow on August 23–24. In a secret protocol of this pact, the Germans and the Soviets agreed that Poland should be divided between them, with the Western part of the country going to Germany and the eastern two-thirds being taken over by the USSR. Read more here.
See similar examples of the Russian historical revisionism concerning this issue such as the Signing of the Molotov-Ribbentrop pact thwarted the UK’s expansionist plans in Europe, The Molotov-Ribbentrop pact did not violate the rights of the Polish state, The shift of all blame for WWII outbreak at the Ribbentrop-Molotov pact the best example of manipulation of history.