This is a flag used by the Union of Polish Tatars (Zwiazek Tatarow Polskich or Polonya Tatar Birlik), the foremost organization of the remnants of a once prosperous and influential ethno-religious group of the Polish-Lithuanian Commonwealth.
Polonya Tatar Birlik is Turkish. Their flag is like our flag. Polish people suppose Tatars are Mongols. No, they are not. They are Turkic. A Turc and a Tatar can understand each other easily when they talk.
Turks and Polish like each other because we have common things in history. Not only Tatars or Ottomans but also Huns. Meanwhile, There is a Polish village in İstanbul called Polonezköy ( Polish : Adampol )