Anadolu Agency said 20 people who "reacted against" the march were among those detained Sunday. Ultranationalist and religious groups had threatened the 15th Istanbul LGBTI+ Pride March in the week leading up to it.
Organisers said 25 people who tried to go on with the banned event were also detained, including two minors and a Danish activist. They were released after questioning.
Police set up checkpoints to prevent people from entering Istanbul's main thoroughfare and marching en masse. Police also used tear gas and plastic bullets on groups of participants.
"Although a demonstration may annoy or cause offense to persons opposed to the ideas or claims it seeks to promote, this cannot serve as an admissible ground for prohibiting a peaceful gathering," the Council of Europe's Commissioner for Human Rights, Nils Muiznieks, said in a statement Monday.
"By banning the event, the Turkish authorities have failed to fulfill their positive obligation to guarantee both public security and the freedom of assembly, to which everyone is entitled, including LGBTI persons and other supporters of their rights," Muiznieks said.