French Montana -- Throws J. Lo Huge Post-Show Bash

French Montana might soon be able to add "party planner" to his resume ... the rapper threw a big time shin-dig for Jennifer Lopez in Vegas.

It all went down Friday night at the Paris Hotel. Montana shut down Martorano's Restaurant for the event. It was all to celebrate J. Lo's opening weekend of her stint at Planet Hollywood.

We're told there was plenty of food, booze and good times to be had by all.

The singer has another nearly sold out performance Saturday night.