Law enforcement sources tell TMZ ... LAPD received multiple calls about loud music and cars double-parked all over Chris' neighborhood in the San Fernando Valley. He turned 32 on Cinco de Mayo but neighbors apparently reached a boiling point in the wee hours of the morning.

We're told cops showed up to the crib Thursday around 2 AM and talked to CB's security. Our sources say the music was turned down but that also spelled the end of the shindig ... which cops estimated had between 400 and 500 guests in attendance.

As you can see from the video ... LAPD showed up in force, with squad cars all over the place directing a massive traffic jam as limos and fancy cars zig-zagged their way out. We're told parking tickets were also issued to improperly parked cars.

You can see a helicopter also hovered above the area ... even more noise for those sleepy neighbors. Cops are all too familiar with CB's crib. In fact ... our sources say 4 police cars and a supervisor were sent over given the troubled history surrounding the pad.

As we've reported ... cops did a welfare check after Chris posted his address on social media during his February 2019 beef with Offset. Cops were also called after CB threw a massive yard sale at his pad back in November 2019.