From NetFlix:

Okwe (Chiwetel Ejiofor), an illegal immigrant working as
a night porter at a posh London hotel, stumbles across
evidence of a bizarre murder. He and Senay (Audrey Tautou),
a Turkish chambermaid — and fellow undocumented worker —
venture into the city’s seedy underworld to find out what
happened. Stephen Frears directs this gritty urban thriller.

This film is not for the squeamish. But if you are into revenge, the ending is very satisfying. Such a great villain! Not feel-good and not for children.