Meek Mill Sued -- Baller Grammy Party Was Strictly Forbidden ... Landlord Wants Payback

Meek Mill threw a rager for 1,000 people on Grammy weekend -- in one of the most baller mansions in Beverly Hills -- only problem is, he ignored the landlord's strict rule: NO PARTIES! So now he's getting sued.

TMZ broke the story ... Meek's huge bash in the famous glass mansion ended when a fight broke out, and all the guests poured into the street. It took cops hours to clear the neighborhood. No one was arrested, but Meek got in big trouble with the landlord.

According to the lawsuit ... when Meek and his people signed a week-long lease ... the management company warned them, "not to think about having the Grammy party" on the premises. In fact, the landlord says the lease limited Meek to no more than SIX people on the property.

In the docs, the landlord says the place was left trashed with broken furniture, broken glass, destroyed landscaping -- and even a broken trampoline. You know it's a party if you wreck a tramp, bruh.

The landlord's suing Meek for breaking the lease, for damages, and for roughly 994 people trespassing.