Chris Brown Sues Philippines Concert Organizer for Extortion Plot

Chris Brown claims he's been held up for $300,000 over a show he postponed, but eventually made up, in the Philippines ... so now he's going after the concert organizer in court.

Chris says the trouble started when he was forced to delay a New Year's Eve 2014 gig in the Philippines ... due to a "misplaced passport." He arranged to play the makeup show in July 2015 ... and performed right on schedule.

The next day ... Chris was trying to leave his hotel -- but, according to the docs, he was met by armed men who blocked his exit. Chris says a lawyer for the arena walked up and told him he would be arrested -- unless he wired $300k to a trust fund for Jose Victor Los Banos Biongco.

Chris refused to pay, hired an immigration attorney and eventually got clearance to leave the country. He says on his way to the airport ... Biongco and his reps continued to text, asking for the dough.