California jurisdiction

Landlord enter into a one year lease with tenant. Terms if the lease is for $3,000 a month; does not allow assignment or sub-lease; and also a provision that states no illegal drug use on premises otherwise lease is considered breached.

Few months into the lease, tenant assigns lease to someone else without landlords permission. Knew tenant knows about the terms of the lease.

After assignee took over, he stopped paying landlord and used illegal drugs on premises. When the landlord found out that lease was illegally assigned and that assignee was using drugs on premises, Landlord filed to evict new tenant. Landlord wants rent for remaining 6 months.

Who is liable for what?