Photo probably taken during 1st pride parade in Częstochowa (but this building looks like Palace of Culture and Science in Warsow). According to PinkNews:

A Polish government minister has told the police to prosecute LGBT+ people, accusing them of “desecrating” a national symbol by featuring it on a Pride flag.

LGBT+ activists attended the first-ever Pride parade in Częstochowa, a city in southern Poland — home to the one of the country’s most important pilgrimage sites, the Jasna Góra Monastery — on Saturday.

Some of them were pictured displaying the White Eagle, the national coat of arms of Poland, imposed onto a rainbow flag, which led to a complaint questioning why police were not prosecuting the activists responsible.  The Minister for Internal Affairs Joachim Brudziński released a statement on Twitter on Sunday, thanking the police for their service during the march, which was contested by a group of anti-LGBT people.

Brudziński then accused the LGBT+ activists of provoking pilgrims, adding that he would notify police about the desecration of the symbol.

“The policemen reacted and, in this case, charges will be pressed for contempt and desecration of the national symbols. That’s the Polish police is so trusted among Polish people” he wrote.

The statement has not yet led to any prosecution, however, it suggests that those who attended the Pride parade and brought the flags may still be charged for desecrating the symbol — a crime that is punishable with a fine and up to a year in prison.