The scene turned violent when participants - many brandishing rainbow flags - denounced "the fascism" of President Recep Tayyip Erdogan.
Police then began to forcefully break up the crowd, with some officers firing rubber pellets into the crowd.
Read: Russian MP urges Facebook blockage over rainbow flag
On a fraught day, pro-government protesters attacked a group of journalists covering the event, including an AFP photographer, causing minor injuries.
According to witnesses and the media, police did nothing to stop the attack.
People affected by police tear gas walk in the Istiklal street near Taksim square in Istanbul on June 28, 2015 as they take part in the Gay Pride parade. PHOTO: AFP
Another AFP journalist said she was assaulted by officers when she tried to film the police intervention.
Read: US Supreme Court rules in favour of gay marriage nationwide
Before the march, police closed off access to Taksim Square, the scene of anti-government protests in 2013 - since which all demonstrations in the area have been banned.
This is the 13th edition of the Gay Pride parade in Turkey, which has been held in the past without major incident.
COMMENTS (1)
Comments are moderated and generally will be posted if they are on-topic and not abusive.
For more information, please see our Comments FAQ