Justin Bieber -- Grilled Like a Cheeseburger ... Over Miami Pap Fight

Justin Bieber better grab a warm jacket ... because he's about to get the third degree -- courtesy of the lawyers repping the Miami pap who's suing the singer for battery.

Bieber just arrived for his deposition in the lawsuit filed by photog Jeffrey Binion, who claims Bieber's bodyguard Hugo Hesny choked him and stole his camera equipment last June outside a Miami recording studio. Binion claims Bieber ordered the attack.

The deposition is going to be ruthless -- sources tell us, Binion's lawyers are ready to go to war and are planning to ask Bieber hundreds of questions about EVERYTHING ... not just the Miami incident.

We're told the lawyers will cover every other pap scuffle ever -- including the most recent one in Atlanta -- as well as Bieber's drug use. And it won't end there either.